TomTom One V3 connector pinout

The TomTom data connector uses a non-standard 2.5mm audio style jack that has four poles on the inside and two around the outer sheath. I have been unable to find a convenient source for the connectors so will remove and replace with a cable to mate with a Digilent PmodRS232 adapter to perform 3.3V TTL to RS232 conversion during debugging. I’ve done some work with a scope and resistors to determine the pin functions for at least the pins I require. The connector viewed from the top of the PCB looks like this:

TomTom One V3 connector pinout
TomTom One V3 connector pinout

Pin functions were determined as:

1 = RX data in for UART ttySAC0, default rate = 115200, 3.3V TTL.

2 = Power output for accessory, I tested sourcing 100mA will no ill effects on unit.

3 = TX data out for UART ttySAC0, default rate = 115200, 3.3V TTL.

4 = Measured 1.4V output, most probably an audio line output.

5 = When connected to ground via a 1K resistor the unit reports an external line input, so presuably that’s what it is.

6 = Ground.

7 = Function unknown but when connected to ground via a 10K resistor it caused an immediate shutdown of unit.

4 thoughts on “TomTom One V3 connector pinout

  1. I am looking to setup an audio output from my TOM TOM One V3 to my bike intercom and was wondering if the audio ouput pin you mentioned actually gets the audio instructions from the navigator. If so how might I get access to this.

    Cheers

    1. Hi Peter, I haven’t actually checked into it but I think the audio pins are for interfacing to the TomTom RDS-TMC Traffic Receiver which I believe is an analog receiver and the TomTom processes the subcarrier messages. As I haven’t be able to find a suitable source for the connectors I had to put an external cable on by TomTom, the easiest solution might be to do the same and pull the audio directly off the internal speaker. Things aren’t really packed inside so you could probably do a neat but warranty-busting job with a small 2.5mm audio jack.

  2. Hi Peter,

    A good solution in getting the connector is buying those old IPod TomTom interface cables. These got all the pins wired and the correct connector. They go for about 10 ~ 20 euros

  3. Hi Peter;

    That magic 7th pin is probably a resistor-based ID pin, the same as your 5th pin is in a 4-wire USB mini-B connector.

    Although a 10k pull-down will cause a reboot, try different resistance levels when connecting the device. Also, this might be the actual function of pin 5: a device ID.

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