SIM900A GSM GPRS Module (RS232 Interface, SMA Antenna)

Where a compact module like the SIM800L is built to tuck directly onto a small project board over a TTL connection, the SIM900A takes a different approach with a full RS232 serial interface and an external antenna connected via a proper SMA jack, suited to projects that already run on RS232-based control electronics or that need the antenna mounted somewhere with better signal reception than the board's own location allows. It covers the same core GSM/GPRS capability, SMS, voice, and basic data, but in a form factor built for a different class of integration than a small-board TTL module.