Thanks for doing that direct test from your Tandy 200 to 102. That confirms that the Tandy 200's TELCOM program (and possibly anything that calls the ROM to read the serial port) is different. I hadn't known that before. I think it must be a bug because even a program that uses DSR to find out whether another device is connected shouldn't hang and require Shift-Break.
Are there any ROM experts here who know what the difference is? Maybe it'll be possible to patch the Tandy 200's ROM. By the way, XON/XOFF is pretty much required. As Jim said, TELCOM does not support hardware handshaking. —b9 On Thu, Dec 22, 2022 at 1:14 AM Cedric Amand <[email protected]> wrote: > I'm super interested in those serial problems, but I can't fully grasp > John's phrase below, would you please clarify and elaborate a bit ? > > > 3 wire is all the model 100 / 200 actually uses unless you're using HTERM > > or you like the godlike simplicity of the cable check lockup, or you > cannot disable the cable check in software. > > I often have lockups on my M200, I'm also under the impression (but I'm no > expert yet) that in some way it's serial (in this case null modem) > implementation niside TERM differs from the one of the M102. If I do a > direct null modem (full cable) between a M102 and a M200, with TERM, the > M200 will systematically lockup when the M102 hangs up ( EXIT/F8 ) whereas > the reverse is not true. > This with both ends using (or supposed to use) hardware handshake (and > xon/xoff disabled) > This is pure observation and might be specific to my setup, of course. > > However if you could please elaborate a bit about how the M10x/M200 uses > the serial lines, that would be much appreciated > > I "think" from my hours of fiddling that null modem serial on the > M10x/M200 only works reliably with xon/xoff and the hardware only handshake > (at least in TERM) is flaky on the receiving end. I have yet to try HTERM. > (It's for sure on my todo) > >
