The onboard two set power supply interface VCC5 5V power supply, VCC4 interface, 3.5–4.5V power supply, optional power on self-starting (default), and control start. The onboard SMA (default) and IPXmini antenna interface, SIM900A interface reserved reset. The size of the module is 49*50, all the new and original device. 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 completely follows the design when the design manual.