Been running JS8Call-improved 2.5.1 for a few weeks and having intermittent PTT failures with my Digirig interface to an IC-705. Receiving works perfectly - decoding all traffic just fine - but TX randomly fails to key the radio.

Checked all CAT settings against my working WSJT-X configuration (identical), tested different COM ports, even swapped USB cables. The issue seems specific to JS8Call as FT8 and WSPR work flawlessly with the same hardware.

Using Windows 11, FLRIG for CAT control. Has anyone encountered this with the recent JS8Call-improved releases? Starting to wonder if it's a timing issue with the longer JS8 message format versus the fixed-length FT modes.

Configuration in WSJTx is identical to JS8Call, so that's a good starting point for troubleshooting. Try setting a longer PTT delay in JS8Call - sometimes the newer versions need more time to establish CAT control before keying.

I've seen this with CP210 bridge drivers on Windows. Even if Device Manager shows the port working, try uninstalling and reinstalling the Silicon Labs drivers. Sometimes Windows updates break the USB-serial bridge communication.

Had the exact same issue with my G90 and Digirig. JS8Call-improved was founded by Chris AC9KH to move development forward from v2.3.1 - the new codebase might have changed some timing parameters. Roll back to 2.4.0 temporarily to isolate whether it's version-specific.