23 Mar
2016
23 Mar
'16
4:51 p.m.
On Wednesday (03/23/2016 at 12:57PM -0400), william degnan wrote:
Both of my units are 745 with EIA interface, internal acoustic coupler
and no 20mA. But checking the manual, I don't see any way that you choose
"20mA mode". It's not a switch or input to the processor that might
change the firmware behavior. So I don't think what gets sent on 20mA
would be different than what gets sent on EIA when you press RUBOUT...
A lot of systems in that era used RUBOUT like a backspace operator.
If the terminal sent RUBOUT, the host/OS would interpret that as a
delete character operation and then echo back a backspace, maybe an X,
then accept the new input character.
https://en.wikipedia.org/wiki/Delete_character
Chris
--
Chris Elmquist
The terminal sends ASCII 0x7F when you press RUBOUT. This is a
non-printing
character locally but the remote system can send back whatever it likes
in response to receiving that 0x7F.
What happens when you're in 20 mA mode? That's what it's for, not
serial
comms unless it's mapped specially. i.e. it's for emulating a teletype.
right?