SIMCOM多路复用技术文档：具有GSM和GPRS功能的设备需要同时处理（发送和接受）各种数据流，例如AT指令，GPRS数据流，GSM线路交接数据流等，这些数据彼此独立。 SIM900硬件设计手册：本文档描述了SIM900s的硬件应用接口，包括相关应用场合的电路连接以及射频接口，接口定义，电气性能和结构尺寸的详细信息。-SIMCOM multiplexing technique document: with GSM and GPRS function equipment need to si

The handover procedure is used when there is a need for a cell change when the MS is busy. The network is responsible for making the handover decision and performing the actual handover. To assist in the handover decision the MS will provide th

presentation about handover GSM