Thetis + MMTTY = Hanging PTT

[DG8DP]

Hi all,

I have noticed that my installation of Thetis + MMTY + WinTest occasionally causes an unpleasant error.
Everything works exactly as it should and occasionally Thetis stays on air.
I then have to click on MOX in Thetis to switch off the transmitter.
It can also happen that I want to send a text which appears in the MMTTY window but the transmitter is not switched on.

The whole thing is sporadic and I can't find any way of isolating the problem.
I use com0com for my virtual COM ports and Virtual Audio Cable for audio. These have been working together for years without any problems.

Does anyone have any idea why the RX-TX switching does not work sporadically or has anyone had similar experiences?

[w-u-2-o]

Do you have any of the VAC PTT override options enabled? If so, it's possible that RFI is getting into the hardware PTT input. I had this happen here once upon a time--whenever I ran certain digi modes on 40M it would lock up bad! I fixed it by going to a shielded cable and connector on the footswitch.

[DG8DP]

PTT override is off and PTT Footswitch is connected with a shielded cable.
For testing I reduced Power to 0 W, so RFI isn't the problem.

I also reduced speed at the Com-Ports to 19k2.

[w-u-2-o]

So not RFI. Assuming you are using CAT PTT, the next questions are: is the software reliably issuing CAT PTT commands, and is com0com reliably delivering them?

Is this Win10 or Win11? com0com and MMTTY are both getting pretty long in the tooth.

Windows updates are notorious for damaging drivers. Perhaps try uninstall/reinstall com0com. Or try another virtual serial app like VSPM or Eterlogic VSPE.

[DG8DP]

I took an old backup from 1 month ago that works fine!
After that I update the system and software and it still works without any problem.
I dont understand the difference because it was the same updates and patches like now.

Anyhow, I'll be QRV in WAE RTTY!

[w-u-2-o]

My bet is on driver corruption.