GSM MOdule from Centerion.. Good singal reception and data funcationality

GPRS模块SIM300初始化命令，打电话拨号命令，挂机命令，发短信命令，GPRS连网命令，GPRS网络传输数据命令。包含模块最基本的用法，改变GPRS模块波特率的设置方法，掉电保持不变。-SIM300 GPRS module initialization command, the command dial phone, hang up the command, send SMS commands, GPRS networking commands, GPRS network to transf