What is CDMA?

What is CDMA?
CDMA (Code Division Multiple Access) is one type of wireless communication technology. CDMA uses spread "spectrum technology". The signal is coded, divided-multiplexed, and scattered over a wide range of frequencies sent over a channel and reassembled at the other end. CDMA providers store your phone number and information in their database. This information is downloaded into your cell phone's internal memory. If you purchase a new CDMA phone you must contact your provider in order to have your information downloaded and phone activated.

A SIM card is used with GSM (Global System for Mobile Communications) a competing technology. A SIM card is a removable chip that stores your phone number and data. The SIM card makes it easy to switch to a new phone by simply sliding the SIM out of the old phone and into the new one. There is no need to contact your provider.

CDMA does not support SIM (Subscriber Identity Module) cards as a whole. The exception is a CDMA SIM card called the R-UIM (Re-Useable Identification Module) that was made available in China and will eventually be available worldwide. Future cell phones may have a market that supports both SIM (GSM) and R-UIM (CDMA) cards.

Although CDMA digital technology is faster GSM owns a majority of the market share (75%-82%.) GSM is a more widespread in Europe and Asia. In the United States, Sprint and Verizon networks are CDMA whereas AT&T and T-Mobile are on GSM. Most of Europe uses GSM and so does China. In India, Hutch, Bharti and BSNL are on GSM whereas Reliance and Tata Tele are on CDMA networks.

TracFone Wireless utilizes the AT&T, T-Mobile and Claro networks for GSM phones and Verizon and Sprint for the CDMA models.  HSN Optimus V customers are on the Spint CMDA network.