Telemetry cable

[jolson]

Can the 12" cable connecting the telemetry unit to the RCP be replaced with a longer one? I'm thinking in the region of 6 to 8 feet long.

Is there anything special I should look for in a cable. I've got a load of modem cables with RJ11 connectors on them, will they do?

Cheers

John

[emdash]

Can the 12" cable connecting the telemetry unit to the RCP be replaced with a longer one? I'm thinking in the region of 6 to 8 feet long.

Is there anything special I should look for in a cable. I've got a load of modem cables with RJ11 connectors on them, will they do?

Cheers

John

It took some digging, but I figured this out. The pinouts are in the PDF schematic of the board, which is available on their git-hub page. https://github.com/autosportlabs/RaceCa ... apture.pdf
n the 4th page of the PDF are the connector pinouts. On the 3rd page you can see that the telemetry jacks are connected to an RS232E driver IC. I'm not sure, but I think RS232E is just like RS232 but allows +/- 5 -12 volts instead of +/- 12v.

The pinouts, right-to-left, facing the connector: +5v, rx,tx, Gnd. But you should double-check a mult-meter before taking my word on that.

Some things to note: only four pins, so no flow control. On the other hand, all 4 conductors on the RJ11 jack are present. Finally, the supplied cable is straight-through, while your typical phone cable reverses the ordering on each end.

If you want a longer cable, 3 - 6 ft should be OK, but not much longer than that. If you have connection issues, try a shorter cable.

Make sure your cable has all 4 conductors, and that it's straight through (compare the order of the wire colors on the supplied cable and phone cable so you can see what I mean), otherwise you're swapping power and end to the bluetooth unit!.

[brentp]

You can use a longer cable, but the gauge of the cable will need to be thick enough to transmit power to the telemetry module. We've seen cases where a longer phone cable doesn't cut it when the module demands extra current when transmitting.

And correct, it needs to be wired straight through.

[emdash]

You can use a longer cable, but the gauge of the cable will need to be thick enough to transmit power to the telemetry module. We've seen cases where a longer phone cable doesn't cut it when the module demands extra current when transmitting.

And correct, it needs to be wired straight through.

I wonder if RJ11 was the right choice....It's common, but the wires are like 26 or 28 gauge. Have you found anything like a heavy-duty RJ11 cable?

[brentp]

Absolutely. there are variants network-type cables that has larger gauge wires, but have RJ11/RJ12 connectors instead of RJ45's.

[brentp]

More - The RJ- style connectors accept up to 22 gauge wire if you were doing something custom. But I would try a plain cable to start.

You should be good with a long distance run so long as you put a big enough decoupling capacitor in the local power supply. You can monitor the voltage sag using a meter during normal operation.