Activate RBS

(Note: pause means the * key held in until box appears)
To activate RBS type: [pause] [pause] [pause] 1 1 3 [pause] 1 [pause] [ok]
You now have to press the [MENU] and scroll to the 'Eng Field Options' function with the keys, and enable it.

De-activate RBS

To de-activate RBS type: [pause] [pause] [pause] 1 1 3 [pause] 0 [pause] [ok]
This only works with some versions of software.

These countries has been reported working:

IT (model: F16 HW: 5.2 SW: 2.1)

What's the use of RBS:

Get Distance From Base Station - Place a call, when it is answered, press [MENU] until 'Eng Field Option' is displayed, press [OK], select 'Active Cell', press [OK], press [MENU] until 'Time Adv xxx' appears, where xxx is a number. Multiply this number by 550, and the result is the distance from the RBS (Radio Base Station), in meters.

Get Signal Quality - press [MENU] until 'Eng Field Option' is displayed, press [OK], select 'Active Cell', press [OK], press [MENU] until 'C1' appears. This is the signal quality. If it becomes negative for longer than 5 seconds, a new cell is selected.

Pin Outs

Numbered right to left, keypad up, battery down looking

1. Gnd
2. Pos
3. True data (TD) (input)
4. Complimentary data (CD) (input)
5. Return data (RD) (output)
6. Audio gnd
7. Audio out
8. Audio in