Introduction to CDMA basics

This document is also available in PDF format.

CDMA (Code Division Multiple Access)

Unlike GSM unlocking, CDMA unlocking is more complicated. With GSM unlocking, once you unlocked the phone, it will accept any SIM cards. All the information about the subscriber and the network are contained in the SIM card. However, when you unlock a CDMA phone, it is not enough because you still have to upload something called a PRL (Preferred Roaming List) into the phone so it knows what channels and frequencies to look when searching for a network. The PRL programming is the most important part to reprogram a phone from one network to another. Without the proper PRL file uploaded into the phone, it will not work. After the PRL programming, you can perform a NAM program, which is essentially the phone number of the customer. The NAM can be done on the phone or through software.

For the most part, CDMA phones do not use SIM card. Some new CDMA phones began to use SIM card to store phone books and other subscriber information. However, this type of phone is still uncommon.

Carriers

CDMA network has at least 50% of the American wireless market. Some well known companies are Verizon, Sprint, Alltel, US Cellular, Qwest, MetroPCS, Cricket and Virgin Mobile.

Cricket always had a very liberal activation policy. Cricket will activate any phones that are programmed for its network. Sprint, Alltel and Qwest will not activate a phone that is not sold by them. This is their corporate policy. It has nothing to do with technical compatibility most of the time. That means, even if you could unlock a phone, because it is not listed in their inventory, they will not activate it.

As of late 2007, Sprint and Verizon recently agreed to provide their customers who request SPC unlock code. Verizon also has agreed to open its network to all compatible handsets.

This document will answer the following questions:

How to use a Verizon phone on Cricket?
How to use a Sprint phone on Cricket?
How to use a US Cellular phone on Cricket?
How to use an Alltel phone on Cricket?
How to use a  Qwest phone on Cricket?
How to use a Virgin Mobile CDMA phone on Cricket?

Although this document focus exclusively on Cricket because the result was predictable and reliable, the procedure here can be used for converting a CDMA phone described here from any CDMA network to any CDMA network. The only difference is that you need the network-specific PRL and NAM, which are not difficult to get.

Cricket’s SID in San Diego is 4729 (SID). Cricket’s activation number is *228 from the mobile handset. You can use this number to check if the phone has been successfully prepared to Cricket’s network. Alternatively, some phones cannot be activated by *228. You can test those phones by dialing 611. Generally, if it does not say “Welcome to Sprint or Verizon”, the phone should be programmed right. Sprint and Verizon phones will always identify the network name when you dial 611 so if it’s still on Sprint or Verizon you’ll know right away.

CDMA Terminologies

SPC / MSL – Service Provider Code or Master Service Lock is the service provider code used to prevent the phone from being programmed to another carrier. On some phones you don’t need to know this, while others you must have it. For example, most Samsung phones do not ask for the SPC when you are using the Samsung PST. However, for almost every other brands you will need to either know the SPC or set it to six zeros (000000).

Verizon do not place a SPC on their phones. However, Verizon pre-paid phones all have SPC.

Sprint always has SPC on their phones.

Virgin Mobile has SPC on their phones. Some times this is the numeric equivalent of “VIRGIN”.

NAM - Number Assignment Module, Memory-storage of the phone's number and ESN.

IMSI – International Mobile Station Identification, usually means the phone number

MIN – Mobile Identification Number, usually means the phone number

MDN – Mobile Directory Number, with Cricket, it is different from the phone number, while most other network gives the same MDN as MIN

SID - System Identification, A unique digital code assigned to each cellular system. The home system of each mobile is stored in its internal memory so that the mobile knows when it is a roamer (outside its normal service area)

Share this page:
Del.icio.us

Links to CDMA handset companies: Audiovox Curitel, LG, Samsung, Kyocera, Qualcomm, Motorola, Sanyo Wireless - A subsidary of Kyocera, UTStarcom. Nokia no longer makes CDMA handsets

Links to CDMA network companies: Verizon / Sprint / Cricket / Alltel / U.S. Cellular / MetroPCS / Qwestphone