Motorola d460, 2500, 6200 (Flare), 7500, 8200, 8400 & 8700

IMEI
*#06# displays IMEI on 8700, NOT on 6200, 7500, 8200

To activate RBS:

(pause means the * key held in until box appears)

[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.

To de-activate RBS,

[pause] [pause] [pause] 1 1 3 [pause] 0 [pause] [ok]

This only works with some versions of software. Please report what works and doesn't for you.

Reported working, by country:

d460: IT
6200 Flare: UK (Orange), AU
7500: IT (model: F16 HW: 5.2 SW: 2.1)
8200: ES, AU, NL, BE
8400: IT, NL
8700: AU, IT, SG, DE, ES, ZA
Uses of RBS:

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.

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.