SIM300的封装，对于要用GSM搞硬件开发的人很-SIM300 package, for use GSM engaged in hardware development is used by the person

SIM300硬件电路及应用说明（中英文版），包含英文：SIM300原理图，命令讲解，硬件。中文：详细使用说明，如何连接，如何传输数据。本人亲自整理-SIM300 hardware circuits and application notes (in English), including English: SIM300 schematic diagram, the order on the hardware. Chinese: deta