Bluetooth: Bluetooth is a radio technology that delivers short-range wireless communication between two devices. It is used to connect headsets to cell phones without wires and to link other cell phones and laptops.

CDMA: Code-Division Multiple Access (CDMA) is a more recent digital cellular technology. CDMA is utilized mostly by Sprint PCS and Verizon Wireless.

Coverage: Because service quality can vary by geography, service providers offer a service coverage map based on zip code. Some service providers allow the ability to cancel a service contract due to service quality reasons before a stated number of weeks after initial service activation.

Credit Check: Approval for new service requires a credit check in which the applicant must provide personal information including social security number. Because subscribers pay monthly after service usage, service providers perform a credit check in order to assess the applicant's risk of potentially defaulting on payments. A credit check is not required when replacing or upgrading phones with an existing service provider or purchasing a prepaid phone.

ESN / IMEI: ESN and IMEI are electronic serial numbers that your service provider will use to activate your phone, which are located underneath the phone battery. These verification numbers help service providers check the cell phone's validity and help prevent fraud. If the ESN and IMEI number is reported as stolen, the cell phone will no longer function.

GSM: Global System for Mobile Communications (GSM) is the most popular digital cellular technology worldwide. GSM phones with tri-band technology are called "world phones" since they can be used in many countries. GSM is utilized mainly by AT&T Wireless, T-Mobile, and Cingular Wireless in the United States.

SIM Card: Subscriber Identity Module (SIM) are small cards that work inside cell phones using GSM technology. The SIM cards are typically located below the battery and can easily be removed and placed in another phone, which will then instantly operate using the subscriber's phone number and account.

TDMA: Time-Division Multiple Access (TDMA) is an older digital cellular technology. TDMA is utilized mainly by AT&T Wireless and Cingular Wireless.

Tri-Band: Tri-Band phones function on the worldwide network of GSM digital technology. While the US uses 1900mhz, most of Europe, Asia, and Africa use 900mhz and 1800mhz. Tri-Band phones function on all three frequency bands. Cell phones with tri-band technology are useful when traveling abroad.

Unlocked: An "unlocked" cell phone will work for any service provider that supports the specific technology of the phone, rather than a single service provider. A user switching service providers can keep a phone that is unlocked for the compatible service network.
  • GSM: AT&T Wireless, T-Mobile, and Cingular Wireless
  • TDMA: AT&T Wireless and Cingular Wireless
  • CDMA: Verizon Wireless and Sprint PCS