Transmit with WSTJT-X using CAT method for PTT to controller USB gets errors.

[K7MDL2]

The controller is defaulted to use the Wired PTT input from the radio SEND line to detect TX/RX. When a PC is connected and a program sends a CAT TX cmd to the radio via the controller, the Tx message (1C 00) is passed straight through to the radio, the radio then goes into Tx and grounds the SEND output line. The controller sees the GND and activates the controller PTT output line to downstream amps, band decoder, etc.

Setup:
Connect PC to controller USB.
Connect PC USB to radio for audio.
Set Radio to accept USB DTR as PTT command.
Set WSJT-X PTT method to CAT

Problem:
Pressing WSJT-X Tune button more often than not results in a comm timeout (as seen by a retry button and flash of radio TX icon and TX thus failing).

A 1C 00 01 is sent to the radio on start of TX. The timeout is from not receiving the expected 0xFB (good ack) response and instead receiving an unexpected change to RX (1C 00 00) message. Not sure why the TX on the radio fails so fast to cause this.

Action:
Figure out why the CAT method is failing randomly.

[K7MDL2]

Workaround:

Set WSJT-X PTT method to DTR on radio (audio) USB comm port and it seems to work fine. PC then directly keys radio via USB DTR when then keys controller, same as if using a mic PTT button.