TomTom gps unit?

Hi all.

Seems to me I found the place I have been looking for :-) Problem is I have a spare original TomTom gps unit I would like to use for my boat. The system in my boat (Lowrance) uses common RS232 interface, and standard nmea0183. There are 2 com ports avail. 1) two wires recieve/ground 2) 3 wires recieve/transmit/ground. I can read 5,4 volt dc on the Recieve wires (ground).

Now the big ? Can I cut the cable from the TomTom gps unit and connect it?

Can the 5 volt´s be used to power the unit (my guess is yes), but how do I wire it up?

Hope someone can help me out here... I´m not that used to gps stuff :-) But do have some experience soldering...

thanx

Jepper-DK

[Charlie]

Welcome to our forums.
In theory there should be no problems with what you intend to do.

PIN 1 = GND
PIN 2 = RX
PIN 3 = TX
PIN 4 = 5v VCC

However I couldnt say for sure it will work OK so I take no responsibility should anything go wrong.
I got the pinout information from the documentation supplied with a Seidio G2500 mount which accepts the TomTom cabled receiver on its RJ11 port.

Originally Posted by Charlie

Welcome to our forums.
In theory there should be no problems with what you intend to do.

PIN 1 = GND
PIN 2 = RX
PIN 3 = TX
PIN 4 = 5v VCC

However I couldnt say for sure it will work OK so I take no responsibility should anything go wrong.
I got the pinout information from the documentation supplied with a Seidio G2500 mount which accepts the TomTom cabled receiver on its RJ11 port.

Thanx for the reply, but I still don´t know about the DC wiring. On com port 1 I have only 2 wires. Recieve and ground. The original gps unit only uses these two wires. My guess is that it is taking the 5,4 volt to operate from the recieve wire !?! ... But does that mean that I can just wire 3 and 4 together on the TomTom gps unit? hmm..

[Charlie]

No, you need to provide 5v DC to PIN 4, not from your TX or RX lines. Sounds like you're going to need to provide external power but that's about all I can help with I'm afraid.

Originally Posted by Charlie

No, you need to provide 5v DC to PIN 4, not from your TX or RX lines. Sounds like you're going to need to provide external power but that's about all I can help with I'm afraid.

Thanks, Now I think I will have a go with this. I will use 4 wires then :-) from gps unit: send / ground, and then some external DC supply with 5 volt.

Wish me luck ;-) I might need it...

[Charlie]

Good luck.

Originally Posted by Charlie

Good luck.

And I did work :-)

Now I will build it "for real". I guess I will mount a RJ-11 inside the cabin, and behind that a sealed stepdown converter for the DC. Would be nice and pretty, and then I can still use the gps other places.

Thanks Charlie!