GSM11.11，SIM卡文件介绍的文档，适用于跟SIM卡开关相关的各种产家参考阅读。-SIM card file documents presented for the SIM card switch with a variety of products related to home reference to read.

MD251 MD231G GSM GPRS 模块硬件SPI读写示例-MD251 MD231G GSM GPRS module hardware SPI reader sample