I am trying to get ProTerm 3.1 to work on an enhanced //e and an Apple Super Serial Card in slot 2. It seems like the interrupts don't work properly for ProTerm 3.1, as it only seems to receive a character when it is sending a character. For example, if I type "AT"<enter>, I can sometimes receive an "O" or "K" if I press enter afterwards, especially if the baud rate is low, for example 300 baud. I can use ProTerm 1.1 at 2400 baud and there seems to be no problem, except that ProTerm 1.1 does not support RTS/CTS and so going at a higher baud rate than 2400 baud results in lost characters.
I have tried two different Super Serial Cards. Unfortunately I don't have a //e with a plain 65C02 in it to swap in for the 65802, as I changed it over to a 65802 years ago to use Merlin 8/16, and I don't recall back then having any problem with ProTERM and high baud rates, though that was 30+ years ago and I could be a bit fuzzy about this.
It's a weird problem. I have also tried several ProTERM 3.1 installations from different sources and they all same more or less the same in this respect. Could another card be preventing the IRQ from being issued? Does ProTerm 3.1 use interrupt based IO while ProTERM 1.1 does not?