# PTT fail with DigiPi, Retevis RT95, AT-778UV cable **URL:** \ **Category:** Uncategorized\ **Tags:** anytone-at-778uv, retevis-rt95, troubleshoot-ptt\ **Created:** [July 26, 2025, 3:12pm UTC](https://forum.digirig.net/t/ptt-fail-with-digipi-retevis-rt95-at-778uv-cable/9325 "2025-07-26T15:12:20Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![W3STY](https://forum.digirig.net/letter_avatar_proxy/v4/letter/w/59ef9b/32.png) [@W3STY](https://forum.digirig.net/u/W3STY)\ **Post date:** [July 26, 2025, 3:12pm UTC](https://forum.digirig.net/t/ptt-fail-with-digipi-retevis-rt95-at-778uv-cable/9325/1 "2025-07-26T15:12:20Z")
I am not able to transmit using DigiPi, DigiRig, Retevis RT95, and the DigiRig AT-778UV cable. Not sure how to ensure that DigiPi is using RTS. I have tried setting the rsdio to VOX and that does work, but I am getting some TX when I wouldnt expect it (but to be fair, I am new to this and those might be normal). Rx is working well. I am using the WebChat function of DigiPi to send messages. Any suggestions? ---
**Author:** ![W3STY](https://forum.digirig.net/letter_avatar_proxy/v4/letter/w/59ef9b/32.png) [@W3STY](https://forum.digirig.net/u/W3STY)\ **Post date:** [July 26, 2025, 4:50pm UTC](https://forum.digirig.net/t/ptt-fail-with-digipi-retevis-rt95-at-778uv-cable/9325/2 "2025-07-26T16:50:10Z")
I did check the cable by shorting the base and closest ring - that does acitvate the PTT/TX, so its on the DigiPi and DigiRig side of the system. When I am able, I’ll hook up the DigiRig to a PC and use WSJT-X to check the DigiRig. Does anyone know how to ensure using RTS for PTT in DigiPi? ---
**Author:** ![K0TX](https://forum.digirig.net/user_avatar/forum.digirig.net/k0tx/32/3_2.png) [@K0TX](https://forum.digirig.net/u/K0TX)\ **Post date:** [July 27, 2025, 11:27am UTC](https://forum.digirig.net/t/ptt-fail-with-digipi-retevis-rt95-at-778uv-cable/9325/3 "2025-07-27T11:27:12Z")
Which model of Digirig are you using? Mobile or Lite? Former uses PTT by RTS or PTT by CAT, latter PTT by GPIO3 or internal VOX. ---
**Author:** ![W3STY](https://forum.digirig.net/letter_avatar_proxy/v4/letter/w/59ef9b/32.png) [@W3STY](https://forum.digirig.net/u/W3STY)\ **Post date:** [July 27, 2025, 1:33pm UTC](https://forum.digirig.net/t/ptt-fail-with-digipi-retevis-rt95-at-778uv-cable/9325/4 "2025-07-27T13:33:45Z")
It’s the Digirig Mobile. I did confirm with WJST that I can trigger TX via the RTS test button. That means it a DigiPi issue. I originally used this DigiPi installation with an AOIC. It’s unclear if there are soundcard specific settings in DigiPi as it hides a lot of details to make it simple. I plan to burn a brand new image and set the card as DigiRig from the start. ---
**Author:** ![W3STY](https://forum.digirig.net/letter_avatar_proxy/v4/letter/w/59ef9b/32.png) [@W3STY](https://forum.digirig.net/u/W3STY)\ **Post date:** [July 27, 2025, 7:18pm UTC](https://forum.digirig.net/t/ptt-fail-with-digipi-retevis-rt95-at-778uv-cable/9325/5 "2025-07-27T19:18:23Z")
Good news! A fresh install of DigiPi (1.9.4) with DigiRig Mobile selected during the initialization step worked! I am seeing that many of the initial values cannot really be changed later and obviously there are soundcard settings that are device specific and fixed (unless you know what config files to edit). I still have some questions as a noobie - is the an acknowledge as part of the APRS protocol, because I do see Tx’s that I am not initiating. ---
**Author:** ![webmonkey](https://forum.digirig.net/user_avatar/forum.digirig.net/webmonkey/32/2494_2.png) [@webmonkey](https://forum.digirig.net/u/webmonkey)\ **Post date:** [July 31, 2025, 4:11pm UTC](https://forum.digirig.net/t/ptt-fail-with-digipi-retevis-rt95-at-778uv-cable/9325/6 "2025-07-31T16:11:54Z")
an ack can be requested (messages to auto responders being common). beacons wouldn’t ask for one of course. 🙂 i’m not familiar with the digipi suite but if you have the digipeater on, it will obviously repeat packets it hears that match the digipeating filter/mask. also, APRSIS to RF may be ‘on’ which would gate internet traffic out to RF (again, if matching the filter/mask) good luck, glad it’s working! 🙂 kb0wlf