The computer can give early computer debugging USB module power supply, a very large amount of data under the condition of the recommended current more than 1A.

Standby dozens of MA data can be set to provide dormancy, dormancy of 10MA low power.

Support 2, mobile phone 3, 4G card.

The serial port circuit: support for 3.3V single chip microcomputer. TTL serial port support

3.3 and 5V single chip microcomputer.

The SIM card circuit to increase the SMF05C ESD chip.

Antenna circuit: guarantee short and straight, so as to ensure the signal strength.

PCB display screen printing mark: each interface, convenient development two times, the SIM900/A hardware is completely follow the design when the design manual.

Two power supply interface: VCC5, 5V DC above 1A.

Computer 5V power supply can be early computer USB.

DC long data circuit over larger recommended 5V1A.

VCC4, 3.5–4.5V power supply, ibid., suitable for lithium battery.

Control pin all leads.

A TTL level, compatible with 3.3V and 5V.

The two antenna interface, the default SMA straight head, connector for IPXmini antenna.

One way of speech interface, the way Mike interface.