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                                 CONTENTS

CHAPTER 1 CHANGES BETWEEN V1.0 AND V1.1

      1.1     DECnet-DOS and DECnet-Rainbow NFT  . . . . . . . . 1-1
      1.2     DECnet-DOS and DECnet-Rainbow SETHOST  . . . . . . 1-2
      1.3     DECnet-DOS and DECnet-Rainbow NDU  . . . . . . . . 1-2
      1.4     DECnet-DOS and DECnet-Rainbow NTU  . . . . . . . . 1-3
      1.5     DECnet-DOS and DECnet-Rainbow TFA  . . . . . . . . 1-3
      1.6     DECnet-DOS and DECnet-Rainbow TTT  . . . . . . . . 1-3
      1.7     DECnet-DOS and DECnet-Rainbow TNTERR . . . . . . . 1-3
      1.8     DECnet-DOS and DECnet-Rainbow DTR/DTS  . . . . . . 1-4
      1.9     DECnet-DOS and DECnet-Rainbow SPAWNER  . . . . . . 1-4
      1.10    DECnet-DOS and DECnet-Rainbow MAIL . . . . . . . . 1-4
      1.11    DECnet-DOS and DECnet-Rainbow FAL  . . . . . . . . 1-4
      1.12    DECnet-DOS and DECnet-Rainbow DIP  . . . . . . . . 1-5
      1.13    Revisions to the DECnet-DOS Programmer's Reference 
              Manual . . . . . . . . . . . . . . . . . . . . . . 1-5
      1.14    DECnet-DOS and DECnet-Rainbow Programming 
              Interface  . . . . . . . . . . . . . . . . . . . . 1-9

CHAPTER 2 SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

      2.1     Asynchronous Installation Problems . . . . . . . . 2-1
      2.2     Asynchronous Performance and Tuning  . . . . . . . 2-6
      2.3     Asynchronous Configuration Problems  . . . . . . . 2-7
      2.4     Ethernet Performance and Tuning  . . . . . . . . . 2-8
      2.5     Ethernet Configuration Problems  . . . . . . . .  2-10
      2.6     General Problems . . . . . . . . . . . . . . . .  2-10
      2.6.1     Problems with Rainbow Only . . . . . . . . . .  2-13
      2.6.2     Problems with IBM PCs Only . . . . . . . . . .  2-13
      2.7     NFT - Network File Transfer  . . . . . . . . . .  2-14
      2.8     Error Messages and Warnings  . . . . . . . . . .  2-15
      2.8.1     Error Messages . . . . . . . . . . . . . . . .  2-15
      2.8.2     Warnings . . . . . . . . . . . . . . . . . . .  2-17
      2.9     SETHOST  . . . . . . . . . . . . . . . . . . . .  2-18
      2.9.1     CTERM ONLY . . . . . . . . . . . . . . . . . .  2-18
      2.9.2     LAT ONLY . . . . . . . . . . . . . . . . . . .  2-19
      2.10    NDU - Network Device Utility . . . . . . . . . .  2-21
      2.10.1    NPDRV - Virtual Printer Driver . . . . . . . .  2-21
      2.10.2    NDDRV - Virtual Disk Driver  . . . . . . . . .  2-22
      2.11    NCP - Network Control Program  . . . . . . . . .  2-22
      2.12    NTU - Network Test Utility . . . . . . . . . . .  2-24
      2.13    TFA - Transparent File Access  . . . . . . . . .  2-25
      2.14    TTT - Transparent Task-to-Task . . . . . . . . .  2-25
      2.15    DTR/DTS  . . . . . . . . . . . . . . . . . . . .  2-25
      2.16    MAIL . . . . . . . . . . . . . . . . . . . . . .  2-25
      2.17    FAL (File Access Listener) . . . . . . . . . . .  2-26
      2.18    DIP - DECnet-DOS Installation Procedure  . . . .  2-28
                                1
      2.19    C Programming Library  . . . . . . . . . . . . .  2-29

CHAPTER 3 MODEM CONTROL

      3.1     Using Modem Control  . . . . . . . . . . . . . . . 3-1
      3.2     Modem States . . . . . . . . . . . . . . . . . . . 3-2
      3.2.1     General  . . . . . . . . . . . . . . . . . . . . 3-5
      3.2.2     State 1  . . . . . . . . . . . . . . . . . . . . 3-5
      3.2.3     State 2  . . . . . . . . . . . . . . . . . . . . 3-5
      3.2.4     State 3  . . . . . . . . . . . . . . . . . . . . 3-5
      3.2.5     State 4  . . . . . . . . . . . . . . . . . . . . 3-6
      3.2.6     State 5  . . . . . . . . . . . . . . . . . . . . 3-6
      3.2.7     State 6  . . . . . . . . . . . . . . . . . . . . 3-6
      3.2.8     State 7  . . . . . . . . . . . . . . . . . . . . 3-6
      3.3     Interface Requirements . . . . . . . . . . . . . . 3-8
      3.4     Modem Option Selections  . . . . . . . . . . . .  3-10

CHAPTER 4 REPORTING PROBLEMS

FIGURES

      3-1     Modem States . . . . . . . . . . . . . . . . . . . 3-4
      3-2     Minimum Implementation of V.24 Circuits for Full 
              Duplex Modem Control . . . . . . . . . . . . . . . 3-7

TABLES

      1-1     Extended Error Messages - Unable to Make a 
              Connection . . . . . . . . . . . . . . . . . . . . 1-6
      1-2     Extended Error Messages - Disconnecting a Logical 
              Link . . . . . . . . . . . . . . . . . . . . . . . 1-8
      3-1     Asynchronous Mode, Direct Connection . . . . . . . 3-8
      3-2     Asynchronous Mode, Modem Connection  . . . . . . . 3-9
      3-3     User-selectable Modem Options  . . . . . . . . .  3-10
                                2

Preface

The following release notes include updated information for DECnet-DOS V1.1 and DECnet-Rainbow V1.1. You should use these notes in conjunction with the material presented in the DECnet-DOS documentation set.

Intended Audience

These release notes are intended for users of the Rainbow series of personal computers and for users of the IBM PC, IBM PC/XT, and IBM Personal Computer AT. Some of the information presented in this document is very technical. If you do not understand the material, you should seek assistance from the person who is responsible for configuring your network.

ALL-IN-1 is a trademark of Digital Equipment Corporation.

IBM is a registered trademark of International Business Machines Corporation.

IBM PC/XT is a trademark of International Business Machines Corporation.

IBM Personal Computer AT is a trademark of International Business Machines Corporation.

MS is a trademark of Microsoft Corporation.

Symphony is a trademark of Lotus Development Corporation.

                                3
                            CHAPTER 1
                  CHANGES BETWEEN V1.0 AND V1.1

This chapter describes the software changes made from DECnet-DOS and DECnet-Rainbow Version 1.0 to DECnet-DOS and DECnet-Rainbow Version 1.1.

For DECnet-DOS only, DECnet-DOS V1.1 adds support for IBM Personal Computer ATs, support for PC-DOS V3.1, and Ethernet support.

In Version 1.0, the background network task was installed as an MS-DOS device driver. In Version 1.1, a number of tasks cooperate to provide background network processing. All of these tasks are terminate and stay resident tasks, not device drivers. They include: the interrupt Scheduler (SCH); the Ethernet Data Link Layer (DLL); the LAT protocol handler (LAT); and the DECnet Network Process (DNP). Note that DLL and LAT apply to DECnet-DOS only.

The processes communicate using software interrupts. The interrupts

                                                          __________

used by each process are listed in an appendix to the DECnet-DOS _ Programmer's Reference Manual. The following sections describe changes to the DECnet-DOS and DECnet-Rainbow utilities. 1.1 DECnet-DOS and DECnet-Rainbow NFT o NFT now provides the PRINT and SUBMIT commands which queue remote files at the remote node, and /PRINT and /SUBMIT switches which can be used with the COPY command to copy local files to remote nodes to be queued at the remote node. o The /FULL switch for the DIRECTORY command now provides a VMS style full directory listing for remote files. 1-1 CHANGES BETWEEN V1.0 AND V1.1 o NFT will now allow you to copy remote files directly to the local printer, for example: NFT COPY REMOTE::FOO.BAR PRN or NFT COPY REMOTE::FOO.BAR PRN: o NFT can now do block mode file copies. Block mode file copying is an image mode file transfer which moves the data in 512 byte units independent of any record characteristics. The end of file byte position is properly retained. This file copy mode may be necessary to copy files with very long records. To use block mode when copying, specify /BLOCK as the only switch. o The date and time of creation of copied files is now preserved. 1.2 DECnet-DOS and DECnet-Rainbow SETHOST o SETHOST now allows you the ability to interrupt a session to perform some local task and then continue the session where you left off. Multiple interrupted sessions are supported (CTERM connections only). Local tasks include any MS-DOS command or sequence of commands, starting or stopping logging of the terminal session, and getting help. o SETHOST now provides VMS style command line editing. o SETHOST provides on-line help. o LAT support is now provided by SETHOST (Ethernet configurations only). When SETHOST attempts to connect to the remote node it first attempts to use LAT protocol. If that fails, SETHOST attempts a CTERM connection. There is no multiple session LAT support. 1.3 DECnet-DOS and DECnet-Rainbow NDU o NDU can now CREATE virtual disk volumes in 4 different sizes, 1.2, 10, 20, and 32 MB. 1-2 CHANGES BETWEEN V1.0 AND V1.1 1.4 DECnet-DOS and DECnet-Rainbow NTU o The SET RECORDING command is no longer available. Use the TO file option instead. o LOOP command syntax has been changed to be more consistent with other DECnet implementations. The LOOP commands are now: LOOP EXECUTOR, LOOP CIRCUIT, LOOP NODE, and LOOP LINE CONTROLLER. 1.5 DECnet-DOS and DECnet-Rainbow TFA o TFA now has on-line help. o TFA can now be unloaded after use to make memory available for other tasks. TNT unloads TFA. 1.6 DECnet-DOS and DECnet-Rainbow TTT o TTT now has on-line help. o TTT can now be unloaded after use to make memory available for other tasks. TNT unloads TTT. 1.7 DECnet-DOS and DECnet-Rainbow TNTERR o TNTERRs name has been changed to TNT. o TNT provides on-line help. o TNT can unload TTT or TFA from memory. 1-3 CHANGES BETWEEN V1.0 AND V1.1 1.8 DECnet-DOS and DECnet-Rainbow DTR/DTS o DTR now has on-line help. 1.9 DECnet-DOS and DECnet-Rainbow SPAWNER o The DECnet Job Spawner is a new utility with DECnet-DOS V1.1. The job spawner runs as a foreground task waiting for incoming connections. When a connection arrives, the spawner looks up the requested object name or number in its database and runs the program which services that type of request. When the program finishes, the spawner again waits for incoming connections. The spawner supports FAL, DTR, and user-written servers. 1.10 DECnet-DOS and DECnet-Rainbow MAIL o MAIL is a new utility with V1.1. MAIL provides you the ability to transmit messages or files to other non MS-DOS nodes in your network. MAIL does not allow you to receive mail directly at your personal computer node. 1.11 DECnet-DOS and DECnet-Rainbow FAL o The File Access Listener (FAL) allows other nodes in your network access to files local to your personal computer node. Access is password controlled. FAL can be run with the Job Spawner. 1-4 CHANGES BETWEEN V1.0 AND V1.1 1.12 DECnet-DOS and DECnet-Rainbow DIP o DECnet-DOS and DECnet-Rainbow can now be completely installed by running the DECnet Installation Procedure (DIP) and answering a few simple questions. Refer to the appropriate installation guide for instructions. _ 1.13 Revisions to the DECnet-DOS Programmer's Reference Manual The following tables are revised Versions of Table D-1 and Table D-2, which are in Appendix D ("SUMMARY OF EXTENDED ERROR CODES") of the _ DECnet-DOS Programmer's Reference Manual. DECnet-DOS supports extended error support to certain socket operations. When you write a program which uses the getsockopt

                                                      __________

function call, extended error codes can be returned in opt_status, a

                __________

data member of optdata_dn. This can occur following an attempted connection request or after disconnecting a logical link.

Table 1-1 lists extended error codes which can be returned following an attempted connection. It lists the error messages found in derrno.h, the decimal value for each message, their equivalent error

           _________            _____

message that dnet_conn returns in errno, and the error reason.

                               1-5

CHANGES BETWEEN V1.0 AND V1.1

Table 1-1: Extended Error Messages - Unable to Make a Connection

Decimal derrno.h dnet_conn

Error Code Mnemonic In errno Reason

0 EREJBYOBJ ECONNREFUSED Connect failed.

                                                        Connection
                                                        rejected by object.

1 EINSSNETRES ENOSPC Connect failed.

                                                        Insufficient network
                                                        resources.

2 EUNRNODNAM EADDRNOTAVAIL Connect failed.

                                                        Unrecognized
                                                        node name.

3 EREMNODESHUT ENETDOWN Connect failed.

                                                        Remote node
                                                        shutting down.

4 EUNROBJ ESRCH Connect failed.

                                                        Unrecognized object.

5 EINVOBJNAM EINVAL Connect failed.

                                                        Invalid object
                                                        name format.

6 EOBJBUSY ETOOMANYREFS Connect failed.

                                                        Object too busy.

10 EINVNODNAM ENAMETOOLONG Connect failed.

                                                        Invalid node
                                                        name format.

11 ELOCNODESHUT EHOSTDOWN Connect failed.

                                                        Local node
                                                        shutting down.

32 ENODERESOURCES ENOSPC Connect failed. No

                                                        node resources for
                                                        new logical link.

33 EUSERESOURCES ENOSPC Connect failed. No

                                                        user resources for
                                                        new logical link.

34 EACCONREJ ECONNABORTED Connect failed.

                                                        Access control
                                                        rejected.
                               1-6

CHANGES BETWEEN V1.0 AND V1.1

Decimal derrno.h dnet_conn

Error Code Mnemonic In errno Reason

36 EBADACCOUNT ECONNABORTED Connect failed.

                                                        Bad account
                                                        information.

38 ENORESPOBJ ETIMEDOUT Connect failed.

                                                        No response
                                                        from object.

39 ENODUNREACH ENETUNREACH Connect failed.

                                                        Node unreachable.

43 ECONNTOOBIG ECONNABORTED Connect failed.

                                                        Connect image
                                                        data field too
                                                        long.
                               1-7

CHANGES BETWEEN V1.0 AND V1.1

Table 1-2 lists extended error codes which can be returned following a

                                                       ________

disconnection. It lists the error messages found in derrno.h, the decimal value for each message, and the error reason.

Table 1-2: Extended Error Messages - Disconnecting a Logical Link

Decimal derrno.h

Error Code Mnemonic Reason

0 EREJBYOBJ The remote node end user

                                   disconnected a  running  logical
                                   link.

8 EABTBYNMGT The logical link was

                                   disconnected by a third party.

9 EUSERABORT The remote end user has aborted

                                   the link.

38 ENORESPOBJ The end user or node at the

                                   other  end  of  the   link   has
                                   crashed or failed.

39 ENODUNREACH The connection has been lost due

                                   to a local timeout.

41 ENOLINK The connection has been lost due

                                   to a protocol failure,  no  such
                                   link found at remote.

42 ECOMPLETE No error. A local end

                                   user-initiated   disconnect  has
                                   completed.
                               1-8

CHANGES BETWEEN V1.0 AND V1.1

1.14 DECnet-DOS and DECnet-Rainbow Programming Interface

    o  The assembler language interface to the  network  process  in
       Version  1.0 was software interrupt 2A (hex).  In Version 1.1
       the interface to the network process is software interrupt 6E
       (hex).  The 2A interface has been retained for compatibility,
       but may be removed in a future release.
    o  A new technique for doing I/O which does not block  is  being
       provided  in Version 1.1, asynchronous I/O.  Asynchronous I/O
       provides a call back  mechanism  to  notify  the  application
       program  that  a request has been completed.  Please refer to
            __________  ____________  _________  ______
       the  DECnet-DOS  Programmer's  Reference  Manual   for   more
       information.
    o  SCBDEF.H
       The  symbol   definition   SCBS_SETOSTAT   was   changed   to
       SCBS_GETOSTAT.
    o  DN.H
       The following definitions for DECnet software components were
       added:
       /*
        * Define DECnet modules as TLA (three letter acronym) strings.
        */
       #define DNMOD_LAT     "LAT"  /* LAT driver */
       #define DNMOD_PDV     "PDV"  /* Port driver */
       #define DNMOD_SCH     "SCH"  /* Real-time Scheduler */
       #define DNMOD_DLL     "DLL"  /* Data Link Layer */
       #define DNMOD_DNP     "DNP"  /* DECnet Network Process */
       /*
        * Define DECnet software module interrupt vectors.
        */
       #define DNMODULE_LAT   0x6a    /* LAT driver */
       #define DNMODULE_PDV   0x6b    /* Port driver */
       #define DNMODULE_SCH   0x6c    /* Real-time Scheduler */
       #define DNMODULE_DLL   0x6d    /* Data Link Layer */
       #define DNMODULE_DNP   0x6e    /* DECnet Network Process */
                               1-9

CHANGES BETWEEN V1.0 AND V1.1

    o  DERRNO.H
       The following symbol definitions were added (note that  these
       are not supported by DECnet-ULTRIX V1.1):
       EUSERABORT      9   - Disconnect: Abort by user
       ENODERESOURCES  32  - Connect: No node resources for new logical link
       EUSERESOURCES   33  - Connect: No user resources for new logical link
       EBADACCOUNT     36  - Connect: Bad account information
       ENOLINK         41  - Disconnect: Protocol failure, no such link
       ECOMPLETE       42  - Disconnect: No error, disconnect completed
       ECONNTOOBIG     43  - Connect: Connect image data field too long
    o  NERROR.C
       Error text for additional DECnet connect  errors  was  added.
       (see new definitions in DERRNO.H)
       The array of character strings, *dnet_errlist[], has changed.
       The  text,  "Connect  failed,  ", which was repeated in every
       string, has been removed and placed  in  a  single,  separate
       character  string,  'connect_error[]'.   If your code indexed
       directly into this global array of strings, you must  account
       for  the  "Connect  failed,  " string in your display code or
       else  use  the  connect_error[]  string.   If  you  used  the
       function  'nerror()', this change will be transparent to your
       program.
    o  DNET_CONN.C
       A 'signal()' function was added for support  of  non-blocking
       connects.   If a 'signal()' function is not supported by your
       C compiler, comment out all references to 'signal' in this  C
       source file before compilation.
                         __________  ____________  _________  ______
       Appendix C of the DECnet-DOS  Programmer's  Reference  Manual
       should include the following entry:
       EINTR   4    Interrupted system call.
                               1-10

CHANGES BETWEEN V1.0 AND V1.1

       Automatic outgoing proxy support was added.  This was done by
       issuing  a  'bind()'  call  to  the  client  socket under the
       following conditions:
       1.  No  access  control  information  passed  in  the  'node'
           argument to 'dnet_conn()'.
       2.  No default access control information found in the  local
           node's node database for the remote node specified in the
           'node' argument to 'dnet_conn()'.
       3.  A user name has been set up for local node in  the  local
           node's database.
    o  The internal function  'dnet_errconvert()'  was  modified  to
       reflect  changes  made  in  DECnet  connect  errors  (see new
       definitions in DERRNO.H) This function  maps  DECnet  connect
       errors to their equivalent 'errno' system error codes so that
       connect  error  returns  from  'dnet_conn()'  will  have  the
       correct  errno  system  error  code in 'errno' for use by the
       function 'nerror()'.
    o  DNMSDOS.H
       ____________
       localinfo_dn  was  revised  to  support  the  complete   path
       specification  for  the  DECnet database path by adding a new
       member to the data structure:
       1.  The complete database path specification is contained  in
           _______________
           lcl_decnet_path.
           _________________
       2.  lcl_decnet_device  is  still  supported   for   backwards
           compatibility.
       3.  See the file for more details on the structure format.
                               1-11

CHANGES BETWEEN V1.0 AND V1.1

    o  DNET_PATH.C
       _________
       dnet_path now supports getting the complete  DECnet  database
       path  specification.   Note that the function's interface has
       not changed.
    o  IOCB.H
       A  new  data  structure,  CIOCB,  was  added  which  supports
       ASYNCHRONOUS NETWORK I/O.  This structure is identical to the
       IOCB   structure   except   for   one   additional    member,
       'io_callback'.    See  the  file  for  more  details  on  the
       structure's format.
    o  TIME.H
       Three new external definitions were added:
       int daylight;
       long timezone;
       char *tzname[2];
       It is  ASSUMED  that  these  are  defined  by  the  user's  C
       compiler.   If  not  used,  comment  them  out of header file
       before compilation(s); otherwise, if not defined, then define
       them in applications programs.
    o  SOCKET.H
       New flag definitions for the CIOCB / IOCB  'io_flags'  member
       were added:
       #define MSG_ASYNC         0x8    /* perform function asynchronously */
       #define MSG_CALLBACK      0x10   /* perform callback */
       #define MSG_NEOM          0x20   /* do not perform end of message */
       #define MSG_NBOM          0x40   /* do not set beginning of message */
       New address family definitions were added:
       #define AF_SES                6
       #define AF_MAX                6
    o  BEGIN.H & FINISH.H
       Segment names were changed in this file.
    o  SIZE.H
       SIZE.H is NOT necessary for V1.1 assemblies.
                               1-12

CHANGES BETWEEN V1.0 AND V1.1

    o  DNETDB.H
       The use of the flags byte in  the  structure,  'dnet_nodeent'
       has  been  modified.   It  is  now interpreted as a bit field
       flags byte.  The new flag symbols are:
       /*
        * dnet_nodeent.dne_delflag - flags
        */
       #define DNET_NODE_DEL   0x2      /* deleted entry          */
       #define DNET_NODE_CRY   0x4      /* encrypted entry        */
       #define DNET_NODE_LAT   0x8      /* LAT preferred host     */
       A new data structure has been added,  'dnet_accent'.   It  is
       the  incoming  access control information entry.  It uses the
       new database file DECACC.DAT.
    o  PRGPRE.H
       The list of header files was modified.
    o  ERRNO.H
       New symbol definition for ASYNCHRONOUS NETWORK I/O errors was
       added:  Check CIOCB 'io_status' field for this value.
       #define NOTHING -2     /* request not complete - asynch i/o */
    o  TYPES.H
       More type definitions were added:
       /*
        * Defines types used in defining values returned by system level
        *  calls for file status and time information.
        */
       typedef unsigned short ino_t;    /* i-node number (not used on DOS) */
       typedef long time_t;             /* time value */
       typedef short dev_t;             /* device code */
       typedef long off_t;              /* file offset value */
                               1-13

CHANGES BETWEEN V1.0 AND V1.1

    o  New function dnet_installed():
       This is a C library function found in source file DNETINST.C.
       It   performs   installation  checking  of  various  software
       components.  See file DN.H for component symbol definitions.
    o  New function dnet_getacc():
       This is a C library function found in source file DNETACCE.C.
       It fetches incoming access control information.
    o  New function csreg():
       This is an assembly function found in source file  CSREG.ASM.
       It  returns  the current CS (code segment) register value and
       works with the 2 segment model only.
    o  New function dnetses():
       This  is  an  assembly  function   found   in   source   file
       DNETSES.ASM.   It  currently  returns  an  incorrect  Version
       number of 0.0 if SESSION is installed.
    o  New function fbcopy().
       This is an assembly function found in source file FBCOPY.ASM.
       It  performs  a  FAR  byte  copy.   It  does  not  check  for
       source/destination buffer overlap conditions.
    o  New function decnet():
       This is an assembly function found in source file DECNET.ASM.
       (V1.0   file   name  was  INTIOCTL.ASM)  It  provides  direct
       interface to the DECnet Network Process (DNP)  via  interrupt
       vector  6EH.   V1.0  interrupt interface to DNP was via 2AH -
       this interface is  still  supported  in  V1.1  for  backwards
                       ________                   _______
       compatibility.  decnet() replaces the V1.0 ioctl() function.
    o  New format for DECNODE.DAT
       The format for the file DECNODE.DAT is different  in  Version
       1.1 than it was in Version 1.0.  Passwords are now encrypted,
       so that other users cannot read any of the passwords you have
       defined.
                               1-14
                            CHAPTER 2
            SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

This chapter describes known problems, restrictions, and troubleshooting hints.

2.1 Asynchronous Installation Problems

    o  When connecting your Rainbow or IBM personal computer to  the
       adjacent  node using an Asynchronous DDCMP connection through
       a null modem cable, remember to switch the send  and  receive
       leads properly.
    o  The use of a terminal switch or a terminal server running LAT
       for  connection  of  your Rainbow or IBM personal computer to
       the adjacent node is not supported.
    o  When  using  the  DECnet  Router  Server   for   asynchronous
       connections,  the circuit must be full duplex and must be set
       to the same line speed as your machine.
       For example:
       Direct:  SET LINE LC-1L SPEED 9600 DUPLEX FULL MODEM NO
       Modem:  SET LINE LC-1L SPEED 1200 DUPLEX FULL MODEM YES
       The circuit cost and hello timer values can  be  set  to  any
       reasonable values.  The state should be set to ON.
    o  When making a direct  Asynchronous  DDCMP  connection  to  an
       RSX11  system,  note  that  entire  controllers  must support
       either terminals or DDCMP lines, but not both.   Insure  that
       your  sysgen  or  system  configuration  does NOT include the
       chosen controller and that your DECnet gen DOES  include  the
       chosen controller.
                               2-1

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

    o  When using Asynchronous DDCMP and connecting  directly  to  a
       VAX/VMS  system,  note  that VAX/VMS can share the lines on a
       controller between terminal support  and  asynchronous  DDCMP
       support.
    o  When  configuring  your  VAX/VMS  adjacent  node,   use   the
       following  commands  as  a GUIDE for your VMS system manager.
       These  commands  establish  the  chosen  terminal  lines   as
       dedicated DDCMP lines.
        
       __ ____ ______ _____ ______ _______ ____ ____ __ ____ _____
       $! Load asynch DDCMP device driver. This must be done after
       __  _____ ______ _____
       $!  every system boot.
       _ ___ _________________
       $ run sys$system:sysgen
       _______ ______________
       connect noa0/noadapter
       ____
       exit
       __ ____ ___ _____ _____ ___ __ __ _________ __ _____
       $! Tell VMS which lines are to be dedicated to DDCMP
       __  ____ ____ __ ____ _____ _____ ______ ____
       $!  This must be done after every system boot
       ____ ____ ___________________________________________ _____
       $set term /protocol=ddcmp/speed=9600/notypeahead/perm ttb4:
       ____ ____ ___________________________________________ _____
       $set term /protocol=ddcmp/speed=9600/notypeahead/perm ttb5:
       __ ___ ___ __ ________ _________ ___ _____ ___ ________
       $! Use NCP to properly configure the lines and circuits
       __  ________ ____ ______ _______ ___ _________ ________
       $!  Remember that DEFINE changes the permanent database
       __  ___ ___ _____ ____________
       $!  and SET works immediately.
       _ ___
       $ ncp
       ______ ____ ______ _____ __ _______ _______ _
       define line tt-1-4 state on receive buffers 4
       ______ ____ ______ _____ __ _______ _______ _
       define line tt-1-5 state on receive buffers 4
       ______ _______ ______ _____ __
       define circuit tt-1-4 state on
       ______ _______ ______ _____ __
       define circuit tt-1-5 state on
       ____
       exit
    o  When  configuring  your  VAX/VMS  adjacent  node,   use   the
       following  commands  as  a GUIDE for your VMS system manager.
       These commands establish all  terminal  lines  as  switchable
       DDCMP lines (V4.2 and later only).
       ON THE VAX
       1.  The asynchronous DDCMP driver, NODRIVER, must  be  loaded
           on the VAX system.
           _______ _______ ______________
           SYSGEN> CONNECT NOA0/NOADAPTER
       2.  DYNSWITCH, the image that controls the switching  of  the
           line, must be installed as a shareable image on the VAX.
       
           ________ ______ _______________________________________________
           INSTALL> CREATE SYS$LIBRARY:DYNSWITCH/SHARE/PROTECT/HEADER/OPEN
                               2-2

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

       3.  A virtual terminal must  be  created  in  order  for  the
           physical   terminal   connection  to  be  broken  without
           actually losing the logical connection  between  the  two
           systems.
           _______ _______ ______________________________
           SYSGEN> CONNECT VTA0/NOADAPTER/DRIVER=TTDRIVER
       4.  The terminal line must be set for 8 bit  characters  with
           no parity and have the attribute DISCONNECT on the VAX.
                                     NOTE
               The  DISCONNECT  attribute  enables  the  virtual
               terminal  to  be  used.  The DISCONNECT attribute
               must be permanent; it must either  be  set  /PERM
               after   every   boot,  or  the  default  terminal
               characteristics must be set properly.  If you set
               the   terminal   characteristics   for  your  own
               terminal, you must log out and log back in  again
               for them to take effect.  Also note that if modem
               control is enabled, hangup must also be  enabled.
               You  know  that  this  step  has  been  performed
               properly  if  your  terminal  device   designator
               begins with VT.
       5.  In the node database, the following  parameters  must  be
           set  for the node that will be switching the asynchronous
           connection:
  1. The INBOUND parameter must be set to either ROUTER or

ENDNODE.

  1. The RECEIVE PASSWORD must be set to match the remote

node's EXECUTOR TRANSMIT PASSWORD.

                                       NOTE
                   The password will be converted  to  uppercase
                   unless it is defined as a quoted string.
    
   _______ ____        _______ _              _ _______ ________         
   NCP>SET NODE node-idINBOUND [router/endnode] RECEIVE PASSWORD password
                               2-3

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

       ON THE PERSONAL COMPUTER
       1.  On a personal computer, the DECnet line must be set  OFF,
           either by default or by command with NCP.
       2.  The terminal line/terminal emulator must be set for 8 bit
           characters with no parity.
       3.  The EXECUTOR TRANSMIT PASSWORD must be set to  match  the
           RECEIVE PASSWORD specified for the node definition on the
           remote system.  The password must be entered in uppercase
           since  the  password  defined  on the VAX is converted to
           uppercase unless it is entered as a quoted string.
                                     NOTE
               The EXECUTOR RECEIVE PASSWORD must  not  be  set;
               when  DYNSWITCH is used, DECnet-VAX will not send
               a password during routing initialization.  If the
               receive  password  is set, the line will not come
               up.
       4.  Both the terminal line and the DDCMP line must be set  to
           the  speed  of  the  line to be used; they will not share
           line characteristics.
       5.  Connect to the VAX as a  normal  terminal  user  using  a
           terminal emulator.
       6.  When the line is to be switched from a terminal line to a
           DDCMP line, the following DCL command is entered:
           ____ ________ ____________________________________
           $SET TERMINAL /PROTOCOL=DDCMP/SWITCH=DECNET/MANUAL
                                     NOTE
               /MANUAL is only used when DECnet must  be  turned
               on  manually.   When  the  switch is initiated, a
               message appears on the terminal  indicating  that
               the  switch  is  taking  place on the VAX and the
               user must exit terminal emulation mode  and  turn
               on the DECnet line.  If the line is not turned on
               within  approximately   4   minutes,   a   static
               asynchronous  line  will  return to terminal mode
               and a dial-up asynchronous line with hangup  will
               be disconnected.
                               2-4

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

       Terminating a Switched DDCMP Connection
       A DDCMP connection created using DYNSWITCH can be  terminated
       from  either  end  of  the  connection by setting the line or
       circuit (VAX/uVAX only) OFF.  The following are  the  various
       scenarios that will occur when the line is disconnected:
       1.  The personal computer user sets the line OFF or the  line
           drops due to noise, etc.
           If the switched line is  a  hardwired  line  between  the
           personal  computer  and  the VAX, or a modem is used with
           /NOHANGUP specified, the circuit on the VAX side will  go
           into  an  ON/STARTING  state for approximately 4 minutes.
           This enables the personal computer user to set  the  line
           back  ON  and  have  it  operational without having to go
           through the entire DYNSWITCH procedure again.
       2.  The system manager on the VAX or uVAX can set either  the
           circuit or the line OFF.
           If either the circuit or the  line  is  set  OFF  on  the
           VAX/uVAX,  both  the  circuit  and  line  information are
           removed from the volatile database and  the  asynchronous
           line is returned to terminal mode.
       Miscellaneous Information
       1.  If a modem is used for a DYNSWITCH connection, the  modem
           signal will not be dropped during the switch.
       2.  If /NOHANGUP is specified on the terminal line, the modem
           signal  will not drop after the DDCMP circuit is set OFF.
           The line will return to terminal mode.
       3.  If DECnet is being turned on manually, a  <CTRL/C>  or  a
           <CTRL/Y>  after the switch message aborts the switch, and
           the line is returned to terminal mode.
       4.  For a dynamic  connection,  the  line  and  circuit  will
           automatically  be  added  to the volatile database on the
           VAX when the line is switched from terminal mode to DDCMP
           mode.   It  does  not  have  to  be manually added to the
           database.
       5.  An asynchronous terminal connection to a  VAX  through  a
           switch  or  a LAT terminal server cannot be switched to a
           DDCMP line using DYNSWITCH.
                               2-5

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.2 Asynchronous Performance and Tuning

    o  If you have a poor Asynchronous DDCMP connection (such  as  a
       noisy  phone  line between modems), the following suggestions
       may help:
                                                    _
       Set the line speed lower (NCP SET LINE SPEED n).
       Set the personal computer's executor retransmit factor higher
                                              _
       (NCP  SET  EXECUTOR  RETRANSMIT FACTOR n).  The default is 6;
       try 10.  This is the  number  of  times  that  a  message  is
       retransmitted  before  the  logical  link is declared broken.
       Setting this parameter higher allows the network  more  times
       to retry messages with errors.
       Set the personal computer's segment  size  smaller  (NCP  SET
                                        _
       EXECUTOR  SEGMENT  BUFFER  SIZE  n).   A smaller segment size
       improves the chances that  messages  will  be  sent  with  no
       errors.   A  smaller segment size also means that the loss of
       one character causes fewer characters  to  be  retransmitted.
       The  VMS  minimum is 192.  Try 200 first.  The minimum of the
       peers is used.  NFT may produce "buffer too small" errors  at
       low values.
       Set the Host's EXECUTOR HELLO TIMER longer.  This affects how
       long  DECnet  will  wait for any traffic before declaring the
       line to be down.
       On VMS, SET CIRCUIT MAX  TRANSMITS  controls  the  retransmit
       count before recycling the line.  Default is 4, set it to 32.
                               2-6

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.3 Asynchronous Configuration Problems

    o  When the network process has the line state  ON,  it  assumes
       that  it  has  complete control of the communications port of
       the system.  It will continue to run DECnet protocols in  the
       background.   If  you wish to use the communications port for
       other purposes (such as a terminal emulator), you must  first
       turn  the  line  state OFF with NCP.  This will disengage the
       network process and return the  communications  port  to  its
       previous state.
    o  The network process uses the communications parameters stored
       in  the DECnet database, NOT the parameters that the port may
       be programmed with by MS-DOS SETUP commands  on  the  Rainbow
       (or  PC-DOS  MODE  commands on IBM PCs).  Problems will occur
       if, for example, you do not properly adjust  the  line  speed
       with NCP to match the remote system.
                               2-7

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.4 Ethernet Performance and Tuning

The Ethernet controllers supported by DECnet-DOS V1.1 use single buffers for message reception. Since the personal computer's CPU is fairly slow compared to the speed of the Ethernet, it is possible for a message to be lost by a personal computer because it is busy getting the last message off of the controller. When this happens, DECnet will detect that a message has been lost (after a short time has passed) and automatically retransmit the lost message. This loss of messages and subsequent recovery can be observed in counters displayed by NCP and NTU, in failures in Ethernet loop circuit commands in NTU, and in short pauses during normal operations. These symptoms do NOT indicate correctable problems. The loss of messages and subsequent recovery is expected.

A number of network management parameters can be changed in an effort to improve performance:

    o  In very large networks that include many routing nodes and/or
       many LAT services, each personal computer may have to receive
       a number of messages which are regularly broadcast by routing
       nodes  and  LAT  services.   These messages are necessary for
       normal operations.  However, received data performance may be
       improved   by  preventing  the  reception  of  these  regular
       messages.   Following  are  the  commands  which   turn   off
       reception  of  these messages and the effect of each command.
       Only after all commands have been typed  will  the  potential
       performance improvement be realized.
                _
       1.  LAT /n
                _
           The /n switch to LAT prevents LAT  from  being  told  the
           name  of each LAT service.  If you do not wish to use LAT
           services, just do not run LAT.  If you DO wish to use LAT
                              _
           services, use the /n switch when starting LAT and use the
           LAT-HOST keyword with the NCP SET NODE command to  inform
           LAT  which services should be available.  (This restricts
           your use of LAT services to those with service names of 6
                                                     _
           characters  or  less.) The default is no /n switch, which
           enables the reception of multicast messages.
       2.  NCP SET CIRCUIT SERVICE DISABLED      [ENABLED]
           This command prevents your personal computer  from  being
           able  to  respond to loopback requests or MOP requests at
           the circuit level.  The default is ENABLED, which  allows
           your  personal  computer to receive multicast messages in
           order to provide service functions.
                               2-8

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

       3.  NCP SET CIRCUIT MULTICAST DISABLED    [ENABLED]
           This command causes your personal computer to listen  for
           announcements  concerning  which  node on the Ethernet is
           the router only when the line is started and  only  every
           ten  minutes  for  1  minute  after that.  The default is
           ENABLED, which allows your personal computer  to  receive
           multicast messages concerning routing.
    o  If logical links break, try setting the retry counter in your
       personal computer higher by typing:
       _______ ________ __________ ______ __
       NCP>SET EXECUTOR RETRANSMIT FACTOR 10
    o  If performance seems bursty, try setting  the  delays  before
       retransmission  lower by typing these commands on your remote
       (non-MS-DOS) systems:
       _______ ________ _____ ______ __
       NCP>SET EXECUTOR DELAY FACTOR 32
       _______ ________ _____ ______ _
       NCP>SET EXECUTOR DELAY WEIGHT 3
    o  If performance  seems  bursty,  you  may  also  want  to  try
       lowering  the  number of messages that a remote node can send
       to your personal computer at a time.  Type on  your  personal
       computer:
       _______ ________ _______ ____ _____ _
       NCP>SET EXECUTOR RECEIVE PIPE QUOTA 1
    o  If performance seems bursty, you may also want to try raising
       the  number  of  messages that a remote node can send to your
       personal computer at a time.  Type on your personal computer:
       _______ ________ _______ ____ _____ _
       NCP>SET EXECUTOR RECEIVE PIPE QUOTA 8
                               2-9

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.5 Ethernet Configuration Problems

    o  During power OFF and perhaps power ON,  Ethernet  controllers
       may introduce noise on the Ethernet.
    o  It may not be possible to format floppies on the IBM PC,  the
       IBM PC/XT, or the IBM PC AT while the Ethernet line is in the
       ON state.   The  DMA  of  bytes  to  and  from  the  Ethernet
       controller   may  interfere  with  the  floppy  timing  while
       formatting.  If this seems to be happening to  you,  use  the
       NCP command SET LINE STATE OFF before formatting and then SET
       LINE STATE ON after formatting.

2.6 General Problems

    o  Following  installation,  DECPARM.DAT  contains   information
       specific  to  the  line you are using (either Asynchronous or
       Ethernet).  Each time the DECnet  Network  Process  (DNP)  is
       started,  it  verifies  that  DECPARM.DAT contains the proper
       line information.  If you wish to switch between use  of  the
       Ethernet  line  and  use of the asynchronous line, you should
       keep two copies of DECPARM.DAT:   one  for  Ethernet  (called
       DECPARM.ETH,  for  example), and one for asynchronous (called
       DECPARM.ASY, for example).  Insure that AUTOEXEC.BAT does NOT
       run  the  DECnet Network Process (DNP).  After each boot, you
       can rename the appropriate DECPARM file  to  DECPARM.DAT  and
       then  run  the matching DNP.  If you attempt to use the wrong
       network process  for  the  current  permanent  database  file
       (DECPARM.DAT),  the  error message "wrong protocol type found
       in DECPARM.DAT" will be displayed.
    o  The network takes control of clock interrupts as soon as  the
       scheduler  component runs (SCHPC or SCHRB).  The network also
       takes control of com option interrupts when the line state is
       ON.  Other products which also take control of interrupts may
       not  be  compatible  with  DECnet.   In  order  to  run  such
       incompatible  software,  you must either turn the DECnet line
       OFF with NCP, or prevent the scheduler component  from  being
       run.   Note  also  that  use  of the DECnet virtual disks and
       printer may not be possible during execution of  incompatible
       software products.
                               2-10

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

       If you are using an asynchronous DDCMP connection, note  that
       Symphony  from  Lotus,  as  shipped,  will  cause the network
       circuit to drop and therefore  will  not  allow  use  of  the
       virtual disk and printer.  However, using the INSTALL program
       that comes with Symphony you can make the  changes  necessary
       to  force  Symphony to ignore the communications port when it
       runs.  Run INSTALL to create a new driver set, or  to  change
       an  existing  driver  set.   Delete  the  drivers  for modem,
       protocol, (and for the Rainbow, 7201  asynchronous  support).
       Note  that if you modify an existing driver set, you must use
       the  method  documented  on  (or  about)  page  41   of   the
       Introduction Manual which describes how to use the minus sign
       to remove an option.
    o  The network process determines the system  type  that  it  is
       running  on  by  looking at ROM BIOS locations and/or calling
       the Rainbow software  interrupt  18  hex.   Due  to  hardware
       dependencies,  the  Rainbow  and  IBM  PC  processes  are not
       interchangeable.  An error message will  be  issued  and  the
       process will refuse to run on the wrong system.
    o  The transparent file access capabilities intercept the MS-DOS
       system  call  interface through interrupt 21 hex.  If you run
       other  programs  that  intercept  interrupt  21,   they   may
       interfere with the functioning of the transparent file access
       operations.
    o  Be sure to understand that sockets are not bound to programs.
       Once  a  socket  is  created,  it will stay alive until it is
       closed, even if the program that created it exits.  A symptom
       of too many open sockets is running out of buffer space.  Use
       NCP and  the  command  SHOW  ACTIVE  LINKS  to  display  open
       sockets, and SET ACTIVE LINK STATE OFF to close open sockets.
    o  All utilities accept the node specification as either a  node
       name or node address.  When node name alone is specified, all
       utilities  will  check  to  see  if  default  access  control
       information has been stored by NCP for that node and use that
       access control information to make the  connection.   If  the
       node  address  is  used,  checking for default access control
       information is BYPASSED.
                               2-11

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

    o  All features of  DECnet-DOS  cannot  be  supported  on  small
       memory  systems.   If  you  find that the DECnet Installation
       Procedure (DIP) warns you about having too little memory,  if
       you  find  that  MS-DOS gives you an error message indicating
       too little  memory  after  running  a  utility,  or  if  your
       personal  computer  hangs  after  running  a utility, try the
       following:
  1. Study the appendix in the Installation Guide which lists

each utility, to determine whether it is memory resident

           and its approximate size.
        -  Do not install any unnecessary third party software  that
           is memory resident.
        -  Do not install TTT.  It is memory resident.
        -  Do not install TFA.  It is memory resident.
        -  Do not install LAT.  It is memory resident.
        -  Set the FILES parameter in CONFIG.SYS as low as possible.
           64 bytes are used for each open file.
        -  Set  the  BUFFERS  parameter  in  CONFIG.SYS  as  low  as
           possible.  528 bytes are used for each buffer.
        -  Use NCP to lower the number of logical links supported.
                                    _
           NCP DEFINE EXEC MAX LINK n
  1. Use NCP to lower the maximum number of buffers to

allocate.

                                      _
           NCP DEFINE EXEC MAX BUFFER n
       On a 256K personal computer there is enough room to run  NCP,
       NFT,  NTU,  CTERM based SETHOST, NDU with one virtual device,
       FAL, DTS, DTR, and MAIL if:
  1. FILES=8 in CONFIG.SYS.
  2. BUFFERS=2 in CONFIG.SYS.
  3. EXEC MAX LINKS 2 in NCP.
  4. EXEC MAX BUFFERS 12-14 in NCP.

Note that if DIP detects insufficient memory, it will automatically adjust memory usage parameters in an attempt to fit all components into memory.

                               2-12

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.6.1 Problems with Rainbow Only

    o  The Rainbow can suffer from crashes,  hangs,  memory  errors,
       and  other  problems if it contains bad memory chips.  It may
       be the case that your Rainbow can have bad  memory  which  is
       seldom  used  until DECnet is installed.  (The resident parts
       of DECnet cause more memory to be used.) As a result, it  may
       appear that the DECnet installation is causing these problems
       when it is in fact the memory.  If you are experiencing these
       problems,  have  your  local field service organization check
       your Rainbow for bad memory.
    o  In  order  to  avoid  problems   with   the   firmware,   all
       non-interrupt driven network processing is suspended while in
       SETUP mode.  Staying in SETUP mode for long periods  of  time
       will most likely cause your network sessions to be lost.
    o  The network process uses the Rainbow  MS-DOS  V2.11  Extended
       Communications  BIOS  User Defined Interrupt Service table to
       redirect communications  interrupts  to  it.   Use  of  other
       programs  that  use  the BIOS function to change or reset the
                                             _______  ______   _____
       service  routine  address  (see  the  Rainbow  MS-DOS   V2.05
       ____________  _____
       Programmer's  Guide  for  more  information) will effectively
       terminate DECnet communications if  the  process  is  active.
       For  example:   running  a poly-COM program will modify these
       addresses.  To recover, you must use  NCP  to  set  the  line
       state OFF and then back ON again.

2.6.2 Problems with IBM PCs Only

    o  The SETHOST utility uses interrupt 10H of the IBM BIOS  while
       running  to  control  screen  output, and takes over keyboard
       interrupt 09H to handle keyboard input.  Any  other  programs
       that you may use to enhance the keyboard or display operation
       may interfere with the operation of this utility.
                               2-13

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.7 NFT - Network File Transfer

    o  The algorithm for determining whether  a  file  is  ASCII  or
       image  when  copying from personal computer to remote without
       switches is as follows:  If the first  512  bytes  contain  a
       CR/LF,  the file must be ASCII.  Otherwise, it must be image.
       Note that some image files may appear to be ASCII using  this
       rule.
    o  The SET command for paths on remote ULTRIX systems  does  not
       work.
    o  The use of MACY11 and LSA switches for  remote  DECsystem-10s
       and DECsystem-20s does not work.
    o  If a directory command specifies multiple subdirectories  and
       some  of  them  are  protected,  the  error  message fails to
       display the volume and directory names.
    o  The command DIR REMOTE::  defaults the file specification  to
       *.*.  This produces the correct results on all remote systems
       except ULTRIX.  On an ULTRIX system this only lists the files
       that  have  a  period  in  their  names.  To work around this
       problem, use the command DIR REMOTE::*.
    o  The SHOW command displays any part of a password string which
       follows  an  embedded  space.   This is not a serious problem
       since most passwords do not have spaces in them.
    o  If a wildcarded copy  from  a  remote  VAX  to  the  personal
       computer  specifies a wild file specification which matches a
       directory specification on the VAX, the directory  files  are
       copied  to the personal computer.  These files do not contain
       any useful information and can be deleted.
    o  If a wildcarded copy  from  a  remote  VAX  to  the  personal
       computer  requests  access  to  a  protected  directory,  NFT
       displays a message saying that there was  a  problem  with  a
       temporary file.  This is the wrong message.
    o  If a COPY command which copies files  from  a  remote  ULTRIX
       system  to  a  personal  computer  defaults  the  output file
       specification and  the  ULTRIX  file  specification  contains
       directories,  then  the resulting personal computer file will
       be named incorrectly.
    o  If the value of MRS is set too large (> 1024) then NFT  fails
       in unpredictable ways.
                               2-14

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.8 Error Messages and Warnings

The following error messages and warnings are not listed in Appendix B

                          __________ ______ _____

(NFT Error Messages) of the DECnet-DOS User's Guide.

2.8.1 Error Messages

  1. Address already in use.
  2. Address family not supported by protocol family.
  3. Argument list too long.
  4. Argument too long.
  5. Attribute read error.
  6. Attribute write error.
  7. Bad address.
  8. Bad block on device.
  9. Bad file number.
  10. Bad terminator or bad value for switch:
  11. Bad version number.
  12. Broken pipe.
  13. Cannot close file.
  14. Cannot get JFN for file.
  15. Cannot open local file with DOS reserved names:
  16. Cannot PRINT list of files.
  17. Cannot PRINT local file.
  18. Connection refused.
  19. Connection reset by peer.
  20. Connection timed out.
  21. Destination address required.
  22. Device not available.
  23. Device not found.
  24. Device not ready.
  25. Device or file full.
  26. Disk full or other error in closing file.
  27. Disk full or other error in writing file.
  28. Disk usage exceeds quota.
  29. Error in data type.
  30. Error in file type extension.
  31. Failure to get transmit buffer.
  32. F11-ACP could not access file.
  33. F11-ACP could not create file.
  34. F11-ACP could not mark file for deletion.
  35. File activity precludes operation.
  36. File already open.
  37. File Exists.
  38. File extend failure.
  39. File is currently in an undefined state.
  40. Filename syntax error.
                               2-15

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

  1. File name too long.
  2. File not found.
  3. FSZ field invalid.
  4. Illegal record encountered.
  5. Insufficient network resources.
  6. Invalid DAP message type received.
  7. Invalid DAP message format received.
  8. Invalid file options.
  9. Invalid object name format.
  10. Invalid wildcard context value.
  11. Logical name error.
  12. LPT page limit exceeded.
  13. Message too long.
  14. Mount device busy.
  15. Network capacity exceeded.
  16. Network dropped connection on reset.
  17. Network operation failed at remote node.
  18. Network operation not supported.
  19. Network operation timed out.
  20. NFAR error, FFIRST with dir in progress.
  21. NFAR error, file not open.
  22. NFAR error, FNEXT with no dir in progress.
  23. NFAR error, illegal access.
  24. NFAR error, invalid function.
  25. NFAR error, invalid RATs.
  26. NFAR error, missing ::.
  27. NFAR error, missing quote.
  28. NFAR error, no \\
    or \\*\\.
  29. NFAR error, no more room.
  30. NFAR error, record buffer too small.
  31. NFAR error, socket not found.
  32. No buffer space available.
  33. Node name cannot be longer than 6 characters.
  34. Node is unreachable.
  35. No more sockets available.
  36. No such device.
  37. Not supported by remote.
  38. Operation illegal or invalid for file organization.
  39. Operation in progress.
  40. Operation not supported on socket.
  41. Operation would block.
  42. Parity error on device.
  43. Path and file names not valid for SET, SHOW, or EXIT

commands.

  1. Permission denied.
  2. Protocol not available.
  3. Protocol not supported.
  4. Remote object is too busy.
  5. Result too large.
  6. Socket is already connected.
  7. Socket is not connected.
                               2-16

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

  1. Socket operation on nonsocket.
  2. Socket type not supported.
  3. Spool or submit command file error.
  4. Switches not valid for SET, SHOW, or EXIT commands.
  5. Task not available.
  6. Too many open files.
  7. Unexpected DAP message received.
  8. Unmatched quotes:
  9. Unrecognized local file specification, remote to remote

operations not supported.

  1. Unrecognized object.
  2. Unrecognized remote file specification:
  3. Unrecognized remote file specification, local to local

operations not supported.

  1. Unsupported DAP flag field received.
  2. VFC value must be less than 256.

2.8.2 Warnings

  1. Extra local file names will be ignored.
  2. Extra remote file names will be ignored.
  3. Warning: Destination file name list longer than source list.
                               2-17

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.9 SETHOST

2.9.1 CTERM ONLY

    o  Use of the @ command for batch input is not  fully  supported
       by ULTRIX and RSX hosts.
    o  The VMS command SET TERM/INQ  does  not  work  properly  when
       embedded in LOGIN.COM and the @ command is used.
    o  VMS  TDMS  applications  are  not   supported   under   CTERM
       connections.   VMS  TDMS applications are supported under LAT
       connections.
    o  A protocol-based virtual terminal service can be slower  than
       a  direct  dumb  terminal connection.  Some sequences will be
       faster using CTERM because all  character  operations  for  a
       complete  line will be done locally in the Rainbow or IBM PC.
       Some operations will be slower (such  as  editing  with  EDT)
       because  each  character  typed  causes  a  number  of  CTERM
       protocol messages to be exchanged.
    o  Writing saved session files does not check for disk error.
    o  While command line editing to VMS, if text is inserted  which
       fills  a  line,  the image on the screen does not wrap to the
       next line properly.  The characters sent to the  remote  node
       are correct.
    o  If backspace characters  are  output  which  would  back  the
       cursor  up  before  the  beginning  of  the  line, text which
       follows the backspace characters appears on  the  next  line.
       Text should appear on the same line.
                               2-18

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

    o  For asynchronous  configurations,  characters  are  sometimes
       lost when typing ahead.
    o  The following information applies to IBM PCs only:
  1. VT100 emulation on IBM PCs does not fully emulate a

VT100. Double height and double width text cannot be

           displayed, 132 character width mode cannot  be  selected,
           not all character attributes are available, and the local
           printer is not supported.
  1. The first ALL-IN-1 screen leaves the cursor in the wrong

place. Typing carriage return properly positions the

           cursor.
  1. Not all character attribute escape sequences work

properly. Both black and white and color have some

           problems.
  1. After exiting from SETHOST on an IBM PC, some screen

attributes are not reset to their state before running

           SETHOST, such as color and cursor format.

2.9.2 LAT ONLY

    o  Use of the @ command for batch input is not  fully  supported
       by ULTRIX and RSX hosts.
    o  Use of the @ command for batch  input  is  supported  by  VMS
       hosts.   However,  it  will  not  work  properly  if  the SET
       TERM/INQ command is embedded in LOGIN.COM and the  @  command
       is used.
    o  VMS TDMS applications are supported  under  LAT  connections.
       VMS   TDMS   applications   are  not  supported  under  CTERM
       connections.
                               2-19

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

    o  The following information applies to IBM PCs only:
  1. VT100 emulation on IBM PCs does not fully emulate a

VT100. Double height and double width text cannot be

           displayed, 132 character width mode cannot  be  selected,
           not all character attributes are available, and the local
           printer is not supported.
  1. Not all character attribute escape sequences work

properly. Both black and white and color have some

           problems.
  1. After exiting from SETHOST on an IBM PC, some screen

attributes are not reset to their state before running

           SETHOST, such as color and cursor format.
    o  If backspace characters  are  output  which  would  back  the
       cursor  up  before  the  beginning  of  the  line, text which
       follows the backspace characters appears on  the  next  line.
       Text should appear on the same line.
    o  Connections to RSX-11M-PLUS V3.0 can crash the system.   This
       problem is being solved by patches or future releases of RSX.
    o  Connections to RSX-11M-PLUS V3.0 can break.  This problem  is
       being solved by patches or future releases of RSX.
    o  Connections to the Ethernet  Terminal  Server  V2.1  (reverse
       LAT)  or  earlier  may  break.   This  problem is solved by a
       future release of the terminal server software.
    o  Connections to ULTRIX V1.2 (or earlier)  systems  can  break.
       This  problem is solved by patches or a future release of the
       ULTRIX software.
    o  If the NEW SESSION option  is  chosen  after  typing  ^\<RET>
       during  a  LAT  session,  SETHOST  allows you to create a new
       session.  However,  the  existing  LAT  session  is  aborted.
       (When  a  LAT  session  to  a  VMS  host is aborted, your job
       remains intact.  The next time you log onto the VMS host, you
       can reconnect to the same job.)
    o  When  using  <CTRL/S>  and  <CTRL/Q>  to  pause  output,  the
       response may be slow.  Pressing the <HOLD SCREEN> key (on the
       Rainbow) or the <ALT/F1> key (on an IBM PC)  is  faster,  but
       the response is still not immediate.
                               2-20

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

    o  To send <CTRL/\> to the host system, be sure  to  repeat  the
       sequence  twice.  If you only do this once, SETHOST waits for
       you to press the <RETURN> key.
    o  If you use /CTERM/SAVE, you can only get back to using LAT by
       deleting the file SETHOST.DEF.

2.10 NDU - Network Device Utility

    o  When the NDU CLOSE command is issued  for  a  remote  virtual
       disk  file  which resides on a personal computer running FAL,
       FAL will report the "broken pipe"  error  message.   This  is
       only a warning; no error has occurred.
    o  If a virtual  disk  file  is  created  with  one  NDISK  file
       specification  and  then  an  attempt  is  made to delete the
       virtual disk file using the command:
                   ____       ____
       DELETE NODE node NDISK file
       with a different file specification which references the same
       file  (using logical names, for example), the delete function
       will fail.  Always delete the virtual  disk  using  the  same
       file  specification that it was created with if the delete is
       done for a connected disk.

2.10.1 NPDRV - Virtual Printer Driver

    o  If the remote FAL makes an error, the Rainbow or IBM  PC  may
       hang.  This will very seldom occur.
    o  On IBM PCs use of the virtual printer by the background print
       spooler may hang the system.
                               2-21

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.10.2 NDDRV - Virtual Disk Driver

    o  If the remote FAL makes an error, the Rainbow or IBM  PC  may
       hang.  This will very seldom occur.

2.11 NCP - Network Control Program

    o  Setting the state of the  line  to  OFF  in  an  asynchronous
       configuration  will shutdown network processing, but will NOT
       hang up the phone, even if the circuit's modem  parameter  is
       set  to  full.   If  you must hang up the phone under program
       control, use the NCP command:
       _______ ____ _____ ______
       NCP>SET LINE STATE HANGUP
    o  The executor transmit and receive passwords  and  the  remote
       node  access  control  strings  may  be  quoted  or unquoted.
       Unquoted strings are forced to uppercase.
    o  Please be aware that some combinations of settings for buffer
       sizes,  buffer  counts,  and  timers  may  cause  performance
       problems  or  network  failures.    Please   change   network
       parameters  only to solve specific problems.  If new problems
       occur as a result, change back to the default settings.
                               2-22

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

    o  If you plan to use the SET KNOWN NODES FROM  REMOTE  command,
       be aware that in a large network, the resulting node database
       can be so large that the search time during  connections  can
       be very long.  In a large network, consider only defining the
       nodes you access frequently.
    o  When entering quoted strings as  part  of  the  command  line
       arguments, the quotes are removed.  For example:
       _______ ______ ____ _______
       NCP>SET ACCESS USER "bence"
       With the quotes removed, this results in:
       _______ ______ ____ _____
       NCP>SET ACCESS USER bence
       The username bence is then forced to uppercase.
                               2-23

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.12 NTU - Network Test Utility

    o  The  LOOP  EXECUTOR  command  requires  3  free  sockets  for
       successful   execution.   If  only  one  (or  no)  socket  is
       available, a proper error message is  returned.   If  exactly
       two  sockets  are  available, NTU reports:  "time-out waiting
       for connect".  This  does  not  indicate  a  failure  of  the
       network.
    o  The LOOP CIRCUIT commands  for  Ethernet  configurations  may
       fail  to  loop  some  messages.   This does not indicate that
       there is a problem which needs  to  be  corrected.   Personal
       computers  may  lose messages at times.  DECnet automatically
       retransmits  lost  messages,   but   the   circuit   loopback
       architecture does not.
    o  Access control strings may be quoted or  unquoted.   Unquoted
       strings are forced to uppercase.
    o  LOOP CIRCUIT to the DECnet Router Server V1.0/V1.1 will fail.
       This  does  not  indicate an error.  There is no loop circuit
       server software in the asynchronous router server product.
                               2-24

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.13 TFA - Transparent File Access

    o  One can use TFA to type and copy files as follows:
       TYPE \\f\node\\filespec
       COPY local-file \\f\node\\remotefile
       TYPE \\f\node\\remotefile >localfile
    o  TFA supports only one open file at a time.

2.14 TTT - Transparent Task-to-Task

    o  TTT supports up to 4 logical links at one time.

2.15 DTR/DTS

    o  DTR and DTS are tools used to test the  network  and  measure
       its  performance.   The  documentation  set  does not include
       documentation for DTR or DTS.  However, the fourth floppy  in
       the   distribution   kit  contains  the  file  DTS.TXT  which
       describes the use of these tools.
    o  Interrupt tests to TOPS-20 systems do not work properly.
    o  DTS on a personal computer  reports  sequence  errors  during
       echo tests, both to VAXes and to other personal computers.

2.16 MAIL

    o  MAIL.EXE can only SEND  mail  to  remote  nodes.   It  cannot
       receive mail.
    o  If one attempts to send a  non-ASCII  text  file  as  a  mail
       message,  MAIL  will  not produce a useful error message, but
       instead will behave erratically.
                               2-25

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.17 FAL (File Access Listener)

    o  FAL does incoming access checking only if the file DECACC.DAT
       exists  in  the DECnet database path.  Such a file is created
       the first time the NCP SET ACCESS command is issued.   If  no
       such  file  exists,  or if you have not issued the SET ACCESS
       command, the system's files are  available  to  any  and  all
       incoming access requests while FAL is running.
       The DECACC.DAT file is deleted if the NCP command CLEAR KNOWN
       ACCESS  is issued.  Note that if one clears all entries using
                                         ____
       the NCP command CLEAR ACCESS USER user, the file  will  still
       exist, but have no entries.  In this case, FAL will do access
       checking, but allow access to no users.
    o  Since MS-DOS is a single tasking operating system,  FAL  must
       run to the exclusion of all other application programs.
    o  Some hosts may use as many as 4 logical links  to  perform  a
       single  file  access function.  If you plan to run FAL, it is
       suggested that you  increase  the  number  of  logical  links
       supported.  Type:
       __________ ________ _______ _____ _
       NCP>DEFINE EXECUTOR MAXIMUM LINKS 8
    o  Because MS-DOS  path  specifications  contain  the  backslash
       character  and  directory  names and file names have the same
       syntax, VMS cannot  use  path  specifications  without  being
       surrounded  with  double  quotes.   In  addition, a number of
       restrictions apply when using quoted file  specifications  in
       VMS.  To solve all these problems, FAL accepts VMS syntax for
       file specifications:
       $ DIR MSDOS::\TEST\*.C         will fail
       $ DIR MSDOS::"\TEST\*.C"       will work
       $ DIR MSDOS::[TEST]*.C         will work
       VMS does not understand that \foo is  sometimes  a  file  and
       sometimes  a  directory.   To  avoid  the  problems that this
       causes, always specify file names or use VMS syntax:
       $ DIR MSDOS::"\"                    will fail
       $ DIR MSDOS::"\*.*"                 will work
       $ COPY *.FOO MSDOS::"\DIR"          will fail
       $ COPY *.FOO MSDOS::"\DIR\*.*"      will work
       $ COPY *.FOO MSDOS::[DIR]*.*        will work
                               2-26

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

       VMS  does  not  properly  separate  the  parts  of   a   file
       specification   when  it  does  wildcarding.   As  a  result,
       wildcard copies of files from  a  personal  computer  to  VMS
       using  VMS DCL cannot be done using MS-DOS file syntax.  Such
       copies must be done using VMS file syntax:
       $ COPY MSDOS::"\WORK\*.*" *.*  will fail
       $ COPY MSDOS::[WORK]*.* *.*    will work
    o  FAL does NOT do file locking.  If you will be using  FAL  for
       simultaneous  access  to the same file, insure that all users
       of the file open the file for reading  ONLY.   If  two  users
       attempt  to  open  the  same  file  for  simultaneous  write,
       unpredictable results may occur.
    o  If FAL is run under the SPAWNER, file access from VMS systems
       using  file  lists  may  fail after the first file.  Wildcard
       file access is supported.
    o  When the NDU CLOSE command is issued  for  a  remote  virtual
       disk  file  which resides on a personal computer running FAL,
       FAL will report the "broken pipe"  error  message.   This  is
       only a warning; no error has occurred.
    o  Trapping of hard device errors works for all IBM  PCs.   Hard
       device errors that occur on a Rainbow will cause FAL to stop.
       When FAL stops due to a device error,  all  its  sockets  are
       still  active.   Use  the  NCP command "SET KNOWN LINKS STATE
       OFF" to abort FAL's links and  sockets  before  starting  FAL
       again.
                               2-27

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.18 DIP - DECnet-DOS Installation Procedure

   1.  The following information applies to Rainbows only:
  1. The files DNPETHRB.EXE and LAT.EXE are not a part of the

DECnet-Rainbow product, but are included on the floppies.

           Do not copy these files to your Rainbow.
  1. If you choose to install DECnet files to floppies (such

that loading of NDDRV.SYS and NPDRV.SYS will be from a

           floppy on system reboot), DIP  will  insert  a  dummy  --
           DEVICE=<x>:<path>DECDIP.SYS -- command line in CONFIG.SYS
           because MS-DOS will fail on loading the first driver  but
           will succeed on loading subsequent drivers specified.
  1. Due to problems with MS-DOS and <CTRL/C> interrupt

handling, if a user enters a <CTRL/C> while in DIP and

           chooses to "terminate" DIP, any saved answers will not be
           written  to a saved answer file.  The only way to produce
           a saved answer file is by running DIP to  completion  and
           saving answers "normally".
  1. Numerous <CTRL/C>s may cause unpredictable results.
   2.  The display of disk  usage  after  copying  DECnet  files  is
       incorrect  when copy path and database paths are specified to
       be on different devices.
   3.  If installing DECnet V1.1 and DECnet V1.1  has  already  been
       installed  at  least  once,  database files do not have to be
       deleted from the DECnet default database path  (for  example,
       *.DAT).
   4.  If DIP is used to install DECnet, an existing DECPARM.DAT (if
       found  in the specified DECnet database path) will be deleted
       automatically.
                               2-28

SOLVING PROBLEMS, RESTRICTIONS, AND HINTS

2.19 C Programming Library

    o  dnet_conn():
       This  function's  first  argument  is  a  node  specification
       string,  such  as a node name or node address.  If the string
       is a node address, no default access control information will
       be  passed  with the connect request.  For example, the local
       node's remote node database will  not  be  searched  to  find
       access control information that may be set up for this remote
       node address.
    o  It is necessary  to  recompile/reassemble  the  V1.1  library
       sources and produce a new library against which utilities can
       be  relinked.   This   will   help   to   ensure   that   any
       inconsistencies  or  incompatibilities  that  exist from V1.0
       will go away.
    o  The C code in the  programming  library  uses  long  variable
       names.  Be sure that your compiler can compile such sources.
    o  Functions required for DECnet network I/O are  documented  in
           __________ ____________ _________ ______
       the DECnet-DOS Programmer's Reference Manual.  In addition to
       these documented functions, many other undocumented 'support'
       functions are included as part of the C programming interface
       library found on the last kit floppy (DNETLIB.SRC).
                               2-29
                            CHAPTER 3
                          MODEM CONTROL

The information in this chapter is provided for people who want to know how modem control is implemented. The information is intended for people who understand modem operations.

3.1 Using Modem Control

To use modem control for DECnet on your personal computer, you should make sure that cables and connections conform to the EIA RS-232-C and CCITT V.28 and V.24 standards. (Refer to Section 3.3 of this guide for information about the cables and interface leads to use with these standards.)

The following assumptions have been made for this release of DECnet-DOS:

    o  Connections that were established  before  turning  the  line
       state ON will be maintained.
    o  Connections that still exist when turning the line state  OFF
       will  be  maintained  (unless  the  data  set is specifically
       commanded to hangup).

You should also be aware of the following information:

    o  In the United Kingdom (UK), the R1 relay in modem  number  2B
       is held up for approximately 2 seconds in order to bridge the
       gaps in the ringing signal.  For proper  operation  in  calls
       that   are  automatically  answered,  the  2-second  hold  up
       requires that the amount of time from DSR=ON through  DTR=OFF
       and  back to DSR=ON be at least 5 seconds.  This will avoid a
       false second call seizure.  (Refer to State 7 in Figure 3-1.)
                               3-1

MODEM CONTROL

    o  It is assumed that the terminal has two modes of operation:
  1. data leads only (modem control signals ignored)
  1. full modem control (modem control signals acknowledged)
       The data leads only mode is used for local connections,  such
       as  null  modem  applications.   The  proper mode signals are
       simulated internally to allow the use  of  a  single  control
       flow.  You can choose between the two modes by using a set-up
       parameter.

3.2 Modem States

Figure 3-1 shows the different states for the modem. (State 1 and State 2 refer to power ON and internal self test functions, and are omitted from this diagram for purposes of clarity.)

                               3-2

MODEM CONTROL

Power –> on from any state except off

      |                                         ||

state 1_ OFFLINE Line state –> hangup or Line state –> off | | | | DTR –> off | | RTS –> off | | TXD –> mark | | | | | | | | Disconnect DECnet from hardware COM device Line State=on Connect DECnet to hardware COM device | _ state 3_ IDLE

  DTR --> on _________________________________ 
  RTS --> on _____________                    | 
 ____________             |                   |
      ^                   |                   |
      |                   |                   | 
      |          Modem Control=FULL   Modem Control=NULL ?
      |          and DSR --> on ?     (Data Leads Only)
      |          __________state 5_   __________state 4_ 
      |                                 Assume
      |             Start 30 sec         DSR --> on
      |             and 1 sec            CD  --> on
      |             timers               CTS --> on
      |          __________________   __________________ 
      |               |       |               | 
      |               |       |               |
      |               |   >1 sec and          |
      |               |   CTS --> on and      | 
      |               |   CD  --> on ?  _______state 6_ 
      |               |       |          Data Exchange
      |               |       |         _______________ 
                               3-3

MODEM CONTROL

      |               |       |               |
      |               |      ___________state 6_ 
      |               |         Data Exchange
      |               |      Transmit if CTS=on
      |               |      Receive if  CD =on
      |               |      ___________________ 
      |               |                    |
      |         >30 sec or                 | 
      |         DSR --> off ?              |
      |               |               DSR --> off or
      |               |               CD  --> off for >2 sec ?
      |               |                    |
      |               |                    |
      |               |                    |
      |               |                    |
      |               |                    |
      |               |                    |
      |               |          _____________state 7_
      |                --------->      Disconnect
      |                             DTR --> off
      |                             RTS --> off
      |                             TXD --> mark
      |                             Start 5 sec timer
      |                          _____________________ 
      |                                | 
      |                             > 5 sec ? 
      |________________________________| 

Figure 3-1: Modem States

The following sections explain the modem states that are detailed in Figure 3-1.

                               3-4

MODEM CONTROL

3.2.1 General

The general states include:

    o  1, OFF, or MARK - these relate to the negative voltage at the
       interface pin.
    o  0, ON, or SPACE - these relate to the positive voltage at the
       interface pin.

3.2.2 State 1

This state is entered at power on.

3.2.3 State 2

This state is entered if the terminal is on-line.

3.2.4 State 3

This state exits unconditionally to State 4 if the data leads only mode is selected. If the full modem control mode is selected, State 5 is entered (as soon as Data State Ready, DSR, has come on). The wait for DSR is untimed. State 3 is the state an on line terminal is normally in before connection has been established.

In State 3, the Data Terminal Ready (DTR) and Request to Send (RTS) signals are turned on. In this state, the modem can switch itself on-line only if DTR is ON. The RTS signal is needed by some modems to prepare the transmit channel.

                               NOTE
      In some cases (such as private wire), it  is  possible
      for  DSR  to be ON before DTR is ON.  This is possible
      if there is a manual connection from the modem to  the
      line.
                               3-5

MODEM CONTROL

3.2.5 State 4

In this state, the actual signals from the modem are ignored and forced internally ON (if the data leads only mode is selected). State 6 is then entered.

3.2.6 State 5

This state is entered only after Data Set Ready (DSR) has come ON. This indicates that the modem is on-line. The modem can come on-line either automatically or manually. It will come on-line automatically if there is a call coming in through the automatic answer unit of the modem. It will come on-line manually when you switch from voice to data after you have established an incoming or an outgoing manual call.

Once the modem is on-line, two timers are started. The timers are called T1 and T2. The timers operate as follows:

    o  T1  protects  against  a  non-data  call.   This  is  a   PTT
       requirement in Germany.  If no data link has been established
       within 30 seconds after the modem has gone on-line (State 6),
       an automatic disconnect is initiated.
    o  T2 protects against data transfer  within  the  first  second
       after the modem has gone on-line.  This avoids garbage due to
       transient effects in some older modems.

If Clear to Send (CTS) and Carrier Detect (CD) have both come ON, the link is considered established.

3.2.7 State 6

This state is the normal data exchange state of the terminal when the call is established.

3.2.8 State 7

This is the disconnect state. The disconnect is initiated by loss of carrier (CD) for greater than 2 seconds, or by the loss of Data Set Ready (DSR). The terminal waits 5 seconds, then a new connection is anticipated by entering State 3. This sequence provides a proper disconnection for all known modems.

                               3-6

MODEM CONTROL

Figure 3-2 illustrates the minimum implementation of the V.24 circuits for full duplex modem control.

INTERNAL DTE ISO 2110 MALE V.24 SIGNAL NAME CONNECTOR PIN CIRCUIT (TYPICAL) See State 7 NUMBER NUMBER

                   in Figure 2-1

PROT GND —————-TT——–> 1 PROTECTIVE GROUND 101

   TxD -------------|>----------->  2   TRANSMITTED DATA     103
   RxD -------------<|----------->  3   RECEIVED DATA        104
   RTS -------------|>----------->  4   REQUEST TO SEND      105
   CTS -------------<|----------->  5   READY FOR SENDING    106
   DSR -------------<|----------->  6   DATA SET READY       107

SIG GND ————————–> 7 SIGNAL GROUND 102

    CD -------------<|----------->  8   RECEIVED LINE        109
                                        CARRIER DETECT
   DTR -------------|>----------->  20  DATA TERMINAL        108/2
                                        READY

Figure 3-2: Minimum Implementation of V.24 Circuits for Full Duplex

           Modem Control
                               3-7

MODEM CONTROL

3.3 Interface Requirements

The following tables specify the interface leads which are required to use DECnet-DOS in asynchronous mode, either with a direct connection or with a modem. (The DECnet software will not monitor the modem leads when direct connection is specified. This allows for the connection to a remote node using a null modem, a modem eliminator, or null modem cable. These are cables and devices which may not provide all the signal leads required for a modem connection.)

Following each table is a list of the part numbers for the DEC EIA RS-232 communication cables which will provide these leads.

Table 3-1: Asynchronous Mode, Direct Connection

                                        CCITT V.24     EIA RS-232-C

Pin No. Function Circuit No. Circuit No.

1 Protective Ground 101 AA 2 Transmit Data 103 BA 3 Receive Data 104 BB 7 Signal Ground 102 AB

Communication Cables:

BC22D 6 wire null modem cable (transmit and receive leads crossed

       within  cable, eliminating the need for a separate null modem
       device.)

BC22E 16 wire modem cable BC22F 25 wire modem cable BCC14 16 wire modem cable (with thumb screw connectors) BCC04 25 wire modem cable (with thumb screw connectors)

                               3-8

MODEM CONTROL

Table 3-2: Asynchronous Mode, Modem Connection

                                        CCITT V.24     EIA RS-232-C

Pin No. Function Circuit No. Circuit No.

1 Protective Ground 101 AA 2 Transmit Data 103 BA 3 Receive Data 104 BB 4 Request to Send 105 CA 5 Clear to Send 106 CB 6 Data Set Ready 107 CC 7 Signal Ground 102 AB 8 Carrier Detect 109 CF 20 Data Terminal Ready 108/2 CD

Communication Cables:

BC22E 16 wire modem cable BC22F 25 wire modem cable BCC14 16 wire modem cable (with thumb screw connectors) BCC04 25 wire modem cable (with thumb screw connectors)

                               3-9

MODEM CONTROL

3.4 Modem Option Selections

To use a modem with the asynchronous port, the modem must be configured to match the line characteristics used by DECnet-DOS. For many modems these will be the standard factory settings. Table 3-3 lists some of the user-selectable options you may find on your modem.

Table 3-3: User-selectable Modem Options

                                              Setting for Use with

Option Description DECnet-DOS

Character Length No. of bits used to 10 bits -

                      encode a character.     8  data bits, 1 start
                                              bit, and 1 stop bit.

Speed Indicate/Select Indicate mode: modem Indicate mode. (Pin

                      indicates modem         23, CCITT  V.24  111,
                      speed on pin 12         is never asserted and
                      (CCITT V.24 112).       pin  12,  CCITT  V.24
                                              112, is not monitored
                                              by DECnet-DOS.)

Receive Responds to Allows modem to Enabled (if you want RDL respond to a remote to allow a remote

                      digital loopback        modem test).
                      test request.

Other selectable modem options should be set according to the modem user's guide for the particular modem application you are using. (Other options include a public switched line, a leased line, asynchronous or synchronous mode, etc.).

                               3-10

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