This is a SIM900A hardware design manual, which mainly introduces the features and characteristics of SIM900A module, including application interface, antenna interface, electrical, reliability and RF characteristics, mechanical dimensions, etc.
This manual describes the hardware architecture of the SIM900A GSM module, including pin assignments, power supply requirements, and the operation of key functions such as sleep modes and the real‑time clock. It is intended for engineers designing circuits that incorporate the module.
The document contains sections on power management (e.g., SLEEP#EHK, SLEEP#EH), RTC operation, voltage specifications, and detailed register tables. It also provides reset procedures and mechanical dimensions needed for board layout. This manual is written in Chinese.