at this is either)
17 DC1 Device control #1(maybe they ran out of things to do?)
18 DC2 Device control #2
19 DC3 Device control #3
20 DC4 Device control #4
21 NAK Negative acknowledge (We heard you, b
ize graphic character
representations and cursor control. It is based upon a 256 character set. It inclu... parity, 7-Bit ASCII codes with Mark parity, ASCII Control code
details): ( http://telecom.tbi.net/ascii