Description

• Based on basic sim800c version, aiming for the cheapest and smallest.
• Total board size is 22.5 * 21 mm, the “hangout” is 15.5 * 3mm.
• Can use standard 2.54mm pin head, or solder vertically on your main board.
• Pin Deifnition – Boot key, VBAT, ADC, GND, TX, RX
• Boot key can be drived by MCU IOs.
• 3.3/5V compliant Serial UART interface.
• Vbat 4.2V power supply, if power from 5V, can use a diode 1N400x to drop voltage to 4.2V, see more on wiki page. DC-DC, confirmed this by simcom.
• sim card size 
• Netlight LED on backside of the board.
• Solid 680uF/6.3V tatanlum capacitor to against current burst.
• IPEX GSM connector.