IMEI (Int. Mobile Equipment Identity) or Serial =*#06#
Nokia Software Version or identify your phone= *#0000#
Phone Secret Menu = *#92702689#
for samsung = *#9999#
To change to anotherr network = #3370#
**61*Your own GSM no. # = Do this on someone's no. to tape his conversation. To cancel this command, #002# and ok This requires fund in both phones.
To unlock a phone, you must know the IMEI/serial, Mobile Country Code (MCC) and Mobile Network Code (MNC). MCN for MTN, Celtel, MTel, and Glo are 30, 20, 40 and 50 respectively. They all use 621 as MCC.
To bring back network = *0000# send
GSM unlocking software include Twister, Alpha black box, Tonash, Universal box, Power plasher, Griphine, Mestroix, Champion, Motorola smart clip, All sagem code reader.
Philip software version = #8377*#
Samsung fault detection = *#0324#
Samsung dark screen correction = *#0523#
Samsung sw version = *#9999#
To hide your no. = #31# gsm no.
To bar out going calls = *33*0000# To unbar =#33#0000#
To bar inoming = *35*0000# To unbar incoming = #35#0000#

How to use Call Me Back
From your Zain line, dial *140*recipient's number# and then send. The recipient will receive an SMS from your number which reads: "please call me back".

How to use Credit Me
From your Zain line, dial *141*8*recipient's number# and then send. The recipient will receive an SMS from your number which reads: "Please Credit Me". It is free to initiate a Credit Me request and you can send up to 10 requests in a day

How to activate call forward
Type **002*[Forward Number]#

How to deactivate call forward
Type ##002#
Text internet to 232 to stop unnecessary billing as a result of internet phone compatibility for zain

How to activate voicemail
It only takes a minute to activate your voicemail: Dial 333122 Follow the spoken instructions to activate your voicemail
You will receive an SMS notification when your voicemail has been activated
Set your 4-digit PIN code.
Record an outgoing message for your callers (something like: 'I can't answer the phone right now. Please leave me a message'). Follow the spoken instructions to further customize the service if you like.

How to divert calls to your voicemail
You can divert your incoming calls to voicemail so that callers can leave you a message. It's a good idea to do this if you are not available to answer the phone. The voicemail service will automatically take messages if your phone is switched off or if you are outside the coverage area.

How to divert calls to voicemail
Open your phone's main menu
Select Call Divert
Choose the option you would like (divert if busy, divert if not answered, divert if out of reach, etc)
Select Activate, Divert to number e.g. +2348020100156

To check your SIM number
FOR MTN Nigeria you should Dial *123*1*5#
FOR ETISALAT Nigeria Dial *248#
FOR GLO Nigeria Dial *135*8#
FOR AIRTEL NIGERIA Dial *405#

Sell N Share or Me to You
MTN: SMS transfer 08033017538 amount PIN t0 777
AirTel: Send a text message in the following format to 432:
2u [space] <phone number> [space] <amount> [space] <PIN>
E.g. To transfer N50 worth of airtime to subscriber 08021234567, the text sent will read:
2u 08021234567 50 1234 (where PIN is 1234)