*ONSTAR* Cellphone mod
 

anyone know if this is possible/can be done? I'd like to use the existing Onstar antenna and plug it in a car kit using the car's speakers for sound output and the built in Onstar MIC as the phone's mic.

I've search...nothing shows up.

tia!

Could you possibly rewrite that ?I assume you want to make calls using onstar? Does it not already have that capability?

Jens

All the schematics for the system can be found in the HELMS manual.
I too thought about “hacking into” the roof antennae.
When I had my back seat out I saw where the wire came down from the roof and into the OnStar box.
I guess you could just cut or split this wire and splice in your car kit.

Using the SPEAKERS would be much more tricky.
THAT would involve splicing into the audio system and NAV box.
I hadn’t planned to do THAT.

Jens,
I think he’s thinking the same as me. Use the HARDWARE (mike & antennae), but not the system.

OIC ok yeah I guess you could use a splitter from radio shack to break the antenna cable to two seperate lines .

Jens

yes sir, that is what i meant to ask. Now would it be easier to use the speaker/mic that come with the cell phone car kit rather than tapping into the system speaker/onstar mic? I've seen it done on a SAAB with onstar. Yes, a UHF splitter of some sort would be required to use the antenna, but where would this Onstar antenna be located? I don't have the HELMS manual :(

The reason for this mod is that Onstar charges you ridiculous monthly recurring service charges and on top of that some ridiculous amount of money for minutes that expire within 2 months.

For example, I have a Sony Ericsson T616 and a car kit. I can use the car kit (it can connect thru the car speakers but it also comes with a microphone). I want to connect the entire car kit via the onstar built in mic and car speakers.

Thanks again!

Ok now that I am on the same page .Take down the front overhead console and you will see a large grey connector ,this carries the microphone wires .Orange/blue is microphone ground and blue/green is microphone input (to Onstar) .Microphone is in the rear view mirror by the way .Antenna is on the roof .It has two cables that go to the Onstar brains behind the left rear seat (you will need to remove the seat to gain access).It is not specified which wire is which .There are two ,one is Onstar the other GPS related .I have never done this so good luck .

Jens

hey jens I put sirius radio in my car would the onstar antenna work for satalite also? or just phone any clue?

No the onstar antenna is just a cell phone antenna on the CL .

Jens

I heard that Onstar utilizes the Analog legacy cell system. If this is so, will the Onstar antenna work with a TDMA or GSM phones?

OnStar does use analog, which is probably around 800MHz..maybe 850MHZ (if I remember my analog correctly). There is TDMA operation at 850MHz as well (I believe) so that should work. But, there's also TDMA at higher frequencies, like 1900MHz. Ditto for GSM. While the antenna might work for 1900MHz, the efficiency of the antenna might suffer, since 1900MHz is not a harmonic of 850MHz.

Anyone know off-hand what frequency band the OnStar system uses? As long as your equipment uses the same band (or a harmonic thereof) you should be OK.

Also, higher frequencies may not work, even at reduced efficiency, if there's an amplifier between the source and the antenna.

it is just a cell phone one the 03 tl with nav also?