bobbO

I read the Tech article for the '99 A4, but it was too confusing. I have a speakerphone thing for my Nokia 8290 that's supposed to plug into the cigarette lighter. Well, today, the connection that goes into the cigarette lighter fell aprt. So, I've decided to hardwire it using the remote turn-on and ground from the armrest telephone jack. My question is: which pin is the remote turn-on lead and which pin is the ground? I'm planning on plugging in a short CAT3 or CAT5 (don't know what fits there as I haven't looked yet) cable into the socket and running it to where I will mount the speakerphone. Thanks everyone!

EdP

meaning that the wires are a direct link to the pins in the DB25 that is in the trunk. They do not connect to anything else. To give the armrest connector funtionality, you need to interconnect pins on that DB25 to reroute what you are looking for into the armrest. The DB25 has pins that are tied to gnd, 12v switched and unswitched power, as well as the Audi speakers, mic and mute signal line at the radio.

Hope that helps.

bobbO

Where could I hardwire this thing then? All I need is remote turn-on and ground... I would prefer not to use the fusebox, but will so if I have to. On my old e36, there was a remote turn-on lead located by the sunroof - a popular location for V1 hardwiring installs. Enough babbling... thanks!

EdP

Like switched 12v power, so that it comes on or charge when you turn on the car?

IN that case, it's very easy. Just take a look at that faq as a reference. Note that pin 3 on the DB25 in the trunk is a ground source, and pin 5 is a switched 12v power source. Now, note that pin 1 of the armrest routes to pin 23 on the DB25, and pin 2 of the armrest routes to pin 8 of the DB 25.

To bring the power to the armrest, you jumper pins 3 and 23 of the DB 225 to make pin 1 of the armrest a ground point. Then you jumper pins 5 and 8 of the DB25 to make pin 2 of the armrest a 12v power source.

An easy thing to do is to get a solder type MALE DB25 connector, make those jumpers I just mentioned, and protect the end from contacting anything - use epoxy or shrink tube.... Plug it onto the DB25 in the trunk,and voila, you got power to the armrest. Use a standard Rj45 from that point on.
Hope that wasn't too crazy.

bobbO

I'm used to connecting stuff like amps to switched power sources... much less complicated than this RJ45/pin/"jumper" stuff... guess I'll forget about hardwiring my $15 speakerphone. Thanks anyway, though! :-)

S4 in Margaritaville

Once you make the right connections on a mating DB-25 coonector, you can run power to the arm rest.

I had a bit of time figuring out, until I looked at the pin outs and understood what was going on there.

I now have my Nokia hooked up, and also 12v to the arm rest, whcih now powers my PDA. I did have to modify the PDA's mobile power cord, adding the RJ45 jack at the end of the cigarette lighter plug.

SPDRMN4

Sonds like you know waht you are talking about. I want to do the same thing with a Motarola V phone. I found an adapter that connect directly into the DB-25 adapter at Best Buy. But how do I get a live conection to the Jack in the rest?