Overview of CDMA modems

Introduction

A CDMA modem is a wireless modem that works with CDMA networks. A wireless modem behaves like a Hayes compatible dial-up modem. The main difference between a standard Hayes modem and a CDMA modem is that a hayes modem sends and receives data through a fixed telephone line while a CDMA modem sends and receives data through radio waves.

A CDMA modem can be an external unit or a PCMCIA card (also called PC Card). An external CDMA modem is connected to a PC through a serial cable, a USB cable, Bluetooth or Infrared. Unlike GSM modems, CDMA modems and phones do not require a SIM card from a wireless carrier in order to operate. CDMA modems are activated by the network once you subscribe to a CDMA service provider.

PC's use AT commands to control a modem. CDMA modems and normal Hayes modems support a common set of AT commands. You can use a CDMA modem just like a hayes compatible modem. CDMA modems support an extended set of AT commands, please note that not all CDMA modems use the same commands for sending SMS ! These extended AT commands are defined in the CDMA standards. With the extended AT commands, you can do things like: