i'm not sure if this is the right address, but maybe you know about it. I currently integrate bluetooth to my car's radio using a esp32. First i wanted to insert the signal at the d2b cd player, but since i don't know the right communication between the occ and the processor i don't see a solution here (and i don't have a cd player to get the reference signals)

But there is a CC player that i can use. There is a detailed documentation about the radio, too: https://www.motor-talk.de/forum/aktion/Attachment.html?attachmentId=753560 Page 12 (or 16 of the pdf)

TRK1R, TRK1L, TRK2R TRK2L and PBREF are used for the signals. CCINS will be GND if there is no CC in the slot and otherwise 5V CCEJT will be 5V if you press the eject button, otherwise it's GND

But this is not enough, there is a tape monitoring circuit that needs to be tricked. Can you see from the documentation how to do so?

CCPSE is connected from the processor to the tapedeck, but i don't know what it is good for CCMOD is connected to the latch 2, UG5V and the tapedeck. It's on 5V while the radio is on. RELL_R and RELL_F are 5V while idle and otherwise they change their value continuously.

CCMET is connected to the CPU, CC Amplifier and the Tapedeck. It's on 5V if the tapedeck is removed and otherwise always 0V. So i short circuit it with GND to simulate there is a tape deck.

CCLDG is connected to the shiftregister and the tapedeck and i have no idea what it is good for. it's always 0V

CCMOT and LED look like they are both the same from the datasheet. They are 0 in general but when the CC is running they turn 5V.

Maybe some can point me out how to trick the tape monitor



1 Answer 1


They make adapters that fit into the Tape socket (if you have one) and will play when you select the audio tape. That is no longer an option on the newer car radios. Mine has an audio input I can use, and it is a 2009 Flex.

  • do you have a link?
    – Stack
    Commented Oct 17, 2020 at 14:18
  • No but you can google it
    – Gil
    Commented Oct 18, 2020 at 2:45

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