IMEI stands for International Mobile Equipment Identifier. If a phone user has an existing phone and wants to use her phone on other network - by checking the IMEI number it can be determined if it will work on that network. This IMEI number can be found on the phone usually behind the battery or outside the box of the phone next to the bar code.
All mobile phones or cellular phones have this unique registration number just like all motor vehicles have a registration number. Another purpose of this IMEI is for network provider to easily allow the handset to be blacklisted in case a customer calls in and report a stolen or lost phone.
The IMEI is 15-digits long and by dialing *#06# on your phone it will reveal its own registration number. In the Philippines, this IMEI code is the one they register in pawnshops in case they pawn their mobile. Amazingly, some phone experts can override this number using software or programs that can be downloaded from the internet and make it possible to activate and use the phone at any network the user desires.
PAC or Port Authorization Code is the code use in order to unlock the mobile phones. When a service provider issued a new customer with a phone, usually the phone is lock in their own network only (service providers like Globe, Smart and Sun Cellular in the Philippines; Virgin Mobile, Orange and Vodafone in UK; Pacific Bell, Verizon and Sprint together with Nextel in the US). If ever the user would like to switch service to another provider she might need to contact the supplier where she got the phone and request an unlock code.
Pressing wrong buttons to unlock the phone may result to finding the right PUK or Personal Unlocking Code, in which the user may need to get in touch with the manufacturer of the phone to unlock it. Again, some phone technicians and experts can override this code using programs available in the market or from the internet. Once the phone has been unlocked, the phone can already be used in any network by using its network's SIM (Subscriber Identity Module).
The PAC is also necessary when the customer is porting a number from her current provider to another provider especially if she wants to keep her original phone number.
Normally, a customer can port as often as she like; the only limit is due to her contract obligations. In order for a customer to port in a number she would need the PAC code; this is the permission of her current network provider to take her number elsewhere. PAC can also be generated via website which some service providers share and make it valid for 30 days.
Three basic things are necessary in porting a number (1) the PAC code, (2) the number they would like to bring, and (3) a SIM pack. A PAC is issued by existing service provider because if the user do not have this PAC code it would not be possible to bring in her number to another provider. But then again, all these methods can be override by systems technology expert on this field.
