Texas Instrument HDX 123.2kHz/134.2kHz (ID4C / TI-RTP)

Hi everyone

I’ve asked this in the Discord a few times but never got an answer so wanted to ask here to see if there’s an official stance on it.

Has anyone started work on reading/emulating TI HDX 123.2/134.2 chips? I think the series name is TI RI-TRP but TI seem to have recently removed a lot of public info on it. It also seems to be the same chip as the “ID4C” transponder sold for use with cars, but they imply some use of cryptography where as the transponder I am trying to read/emulate does not.

I think this is doable in theory, but from looking at other implementations in proxmark it seems like this is going to require a separate implementation from how the current “protocols” work.

If this is possible but a really low priority, I’m not super familiar with RF and the Flipper firmware but if someone could point me in the right direction for how to approach this I’d be happy to have a go myself and at least draft an implementation.

Thank you!

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I am having a hard time finding protocol info on 134KHz tags but I did dig up some things that might be helpful (see below). As far as the RF side of things, since the frequency is bit-banged from the CPU, what about sweeping through the 120-135KHz range while looking for a response? It would take more time, but if that’s an issue it could be a separate menu option.