NOTE: Not my specs, copypasted from ebay for reference.
- Serial interface: TTL/USART serial support.
- Antenna circuit: Three common antenna interfaces (SMA interface only soldered)
- Two way power interface: DC IN 5 v DC power supply OR 3.5-4.2 V power supply, suitable for lithium battery power supply applications.
- Audio interface: increased by 3.5 MM audio interface, easily implement voice calls, voice broadcast, etc.
- SIM booth: new mainstream type metal MICRO thrust booth, strong and durable.
- LED indicator light: onboard two LED indicators. Allows you to monitor module working condition.