KINGMAK-SIM900A-V40-Kit-Wireless-Extension-Module-GSM-GPRS-Board-Antenna-Tested-for-Arduino-UNO-Mega

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.
Support 2G, 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.
The control interface of each pin description: GND - GND SIMR SIM900A RXD, TTL level, can not be directly connected to the 232 level SIMT SIM900A TXD, TTL level, can not be directly connected to the 232 level RST - SIM900A reset, active low VCC_MCU when the SIM900A module and 5V TTL level communication, this pin is connected to DC 5V; when the level of communication of SIM900A and 3.3V TTL, this pin is connected to DC 3.3V. VCC5----DC 5V input. VCC4------DC3.5--4.5 input
Onboard Resources:
Serial port circuit(with protection) Antenna interface circuit(SMA bend female port) SIM card circuit(flip SIM slot)
4*3.5 fixture hole 4pcs SIM900A serial port output terminal
Specifications: Size:49mm x 47mm
Net Weight:28g
Weight: 38g Package

Included:
1 x SIM900A V4.0 kit 1x Power Cable 1x Antenna