I’m trying to get Digirig to work with the Icom 821H for FT8 and there doesn 't appear to be anything online. Receive works via the Digirig cable, but I have some questions about PTT for transmit. I understand I can only use RTS for PTT (which seems odd…there’s a perfectly good pin on the Digirig mic cable plug…)
Do I need to cut the connector on the Digirig board for PTT control?
What kind of cable from the Digirig serial port to the CI-V port on the Icom? A simple 3.5mm stereo cable?
I have a separate CI-V cable that controls frequency but the WSJT-X software doesn’t work for it to use RTS to activate PTT on transmit.
Regular stereo cable should be good for CI-V between Digirig’s serial port and transceiver CI-V/remote socket.
You can use PTT by CAT if supported, but usually PTT by RTS is available option in software including WSJT-X since you mentioned FT8. This method does control PTT line in audio cable.
I cut the traces and soldered the jumpers for CI-V control on the Digirig as per the instructions/video. Now, frequency control works via a TRS cable. However still not PTT via RTS. I measured the voltage and the Digirig is putting out 3.3v at the tip and sleeve.
You must be checking on the serial connector. 3.3V is normal for CI-V.
PTT is on the ring 2 of audio cable. There should be no DC voltage there: sleeve is ground and tip is the audio line decoupled through capacitor. For more info you can check out the schematic at the bottom of this post: