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RT-880 Proof of Concept Audio Injection
🕑 Added 2025-10-01 17:22:50 +0000 UTCThis is EXTREMELY rough and still in the very early stages, but the sound is audible and functional (although there is a weird buzzing which I will need to address)
Here’s how it works: when transmitting, press SP1 (the middle side button), and the regular voice prompt audio samples will be injected directly into the TX audio path.
A few things to note:
On non-GPS versions, it does work, but the audio is very quiet.
This is just the beginning, there’s still a lot of refinement needed.
Despite its early stage, I think you’ll agree this has far more potential than just APRS. Stay tuned as I continue developing this!
UPDATE: POC2 - Injected audio is a lot cleaner, no buzz.
UPDATE: POC3
This one now injects APRS "like" tones, it is Bell 202 but its just random data, nothing that can be decoded yet, it's just to see how it sounds on different radios.
IMPORTANT: Make sure Main Menu -> Advanced -> ARPS Dev is set to a reasonable value as it will probably be 0 to begin with.
The default is 64, but if you are getting quiet audio (non GPS model or early GPS model), try cranking it up to 126.
Comments
Marcus Dudley
How are you streaming TX audio? I never found anything on the 890 that could inject it. With regard to your GPS version, my suspicion is that you have a model with the actual CMX868 chip in it, the louder volumes come from the later models that replaced the chip with something else.
Ramon Martinez Palomares
on my GPS version. audio is very quiet also (one of the first preorders) but this seems really interesting. I have CAT control working over your RT890 version. and i have RT audio streaming over serial implemented. At the moment only used for cw without sidetone. but works. May be this opens the door to digital modes (audio over CAT is only 8khz).
Artur Samborski
nice, I see potential here for a built-in voice keyer or even a voice beacon :)
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