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.

Motorola V3688

*#06# for checking the IMEI (International Mobile Equipment Identity)

Enhanced Full Rate Codec (EFR):

To Enable EFR press [][][] 119 [] 1 [] OK.
To Disable EFR press [][][] 119 [] 0 [] OK

NOTE: Nothing appears on Screen.

Other Phones from Motorola (CD 160, CD 520, 920, 930)

Motorola CD 160

Press menu and type one of these numbers and press OK:

11 = Status Review
13 = Available Networks
14 = Preferred Networks
22 = Select Keypad Tones
25 = Require SIM Card PIN
26 = Language Selection
32 = Repetitive Timer
33 = Single Alert Timer
34 = Set IN-Call Display
35 = Show Call Timers
36 = Show Call Charges
37 = Call Charge Settings
38 = Reset All Timers
43 = Reset All Timers
45 = Show Last Call
46 = Total For All Calls
47 = Lifetime Timer
51 = Change Unlock Code
52 = Master Reset
53 = Master Clear (Warning!! May result in deleting the Message Editor!!!)
54 = New Security Code
55 = Automatic Lock
63 = Battery Saving Mode

Free call tip
1 Enter the phone number
2 Enter OK
3 Type *#06#
4 Press Button C
5 And finally press the button for power off.

You should now be able to talk without being billed.

Motorola CD 520