Using external GSM antenna (on rear fender) with iPhone

[notorious]

Hi everyone,

I have 2002 D2 with phone preparation with external GSM antenna, which is not currently used.



The "box" below antenna mast have 3 connections and all of them are not used

1. Funk, GSM 900-1800, connected with signal amplifier and then with GSM module.
2. RC, 433Mhz. Have no idea what it is. Can anyone explain?
3. FM Radio and +12 DC.

It's kind if strange to have OEM Audi antenna on the rear fender with 3 great connections and none of them is actually used

Do you guys use at least one of these connections for anything? For instance, can I get any iPhone car kit which will allow me to use the external GSM antenna (connection number 1)?

Thanks!