Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

Appendix A 299
Comparing MPE/iX Systems to MPE V Systems
Software Characteristics
Table A-7 Unrecognized AEOR Characters (MPE V)
Transparent Mode
On MPE V computers, the ASCII characters DC1 and DC3 are treated
as data in transparent mode. With MPE/iX, DC1 and DC3 are not
treated as data, but as the protocol characters XON and XOFF.
Binary Mode and Echo
When initiating binary mode (through the FCONTROL27 intrinsic) on
an MPE/iX computer, turn echo off on the device (FCONTROL13). This
is necessary because if a DC3 character is in the data, it will be echoed
and will XOFF the device. Refer to “XON/XOFF Protocol” under
“Software Characteristics” earlier in this appendix for more
information.
Using FCONTROL(35)
The FCONTROL35 intrinsic is used to inhibit the printing of !!!
(three exclamation points) when the line deletion character (
[CTRL]-X
by default) is entered. When the line deletion response is disabled on
MPE V computers, a carriage return and linefeed are sent when the
line deletion request is received, and all read data is disregarded. The
user can start typing the line from the beginning. On MPE/iX
computers, the line deletion request functions the same except for one
thing: the carriage return and linefeed are not sent.
ASCII Character Terminal Keys Octal Code Hex Code
NUL(Null) [CTRL]-@ % 0 $ 0
BS(Backspace) [CTRL]-H % 10 $ 8
LF(Linefeed) [CTRL]-J % 12 $ A
CR(Carriage Return) [CTRL]-M % 15 $ D
DC1(XON) [CTRL]-Q % 21 $11
DC2 [CTRL]-R % 22 $12
DC3(XOFF) [CTRL]-S % 23 $13
CAN(Cancel) [CTRL]-X % 30 $18
EM(End-of-Medium) [CTRL]-Y % 31 $19
ESC(Escape) [CTRL]-] % 33 $1B
DEL(Rubout) % 177 $7F