# FX-4C: digirig in and out both work, but not together

**URL:** <https://forum.digirig.net/t/fx-4c-digirig-in-and-out-both-work-but-not-together/3672>\
**Category:** Uncategorized\
**Tags:** fx-4c, troubleshoot-audio\
**Created:** [May 16, 2024, 6:59am UTC](https://forum.digirig.net/t/fx-4c-digirig-in-and-out-both-work-but-not-together/3672 "2024-05-16T06:59:08Z")\
**Posts on this page:** 1\
**Showing post:** 3

<div class="post-metadata">

**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:** [May 16, 2024, 4:43pm UTC](https://forum.digirig.net/t/fx-4c-digirig-in-and-out-both-work-but-not-together/3672/3 "2024-05-16T16:43:22Z")

</div>

This can be related to the radio’s speaker output using BTL design as discussed here:

> [@Cable for Anytone AT-778UV](https://forum.digirig.net/t/cable-for-anytone-at-778uv/190):
>
> Like in case of many mobile transceivers we’ll need to gather required signals from multiple connectors: The audio must come out of the headphone jack, though there is a bit of a gacha there. The amp uses a [bridge-tied load (BTL) design](https://en.wikipedia.org/wiki/Bridged_and_paralleled_amplifiers) while Digirig expects unbalanced input against the ground. [image] We can either: use an audio transformer from tip and sleeve on transceiver side to primary winding and from secondary winding to ground and RIG\_AFOUT on Digirig…

With only the headphones cable plugged in, can you check that there is continuity between the sleeve contact on the Digirig’s end of the cable and radio’s chassis?

If there is none, then the cable will have to be modified by disconnecting the sleeve on the headphones connector.

---

_[View the full topic](https://forum.digirig.net/t/fx-4c-digirig-in-and-out-both-work-but-not-together/3672)._