On Wednesday (03/23/2016 at 12:57PM -0400), william degnan wrote: > > > > 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?
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
