Description Based on basic sim800c version, aiming for the cheapest and smallest. R1 Vertical Version: 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. No need DC-DC, confirmed this by simcom. Nano sim card size (iphone size) Netlight LED on backside of the board. Solid 680uF/6.3V tatanlum capacitor to against current burst. IPEX GSM connector. R2 Mini Version: Lead out most pins from SIM800C: Pin pitch 2.0mm, board size 27×27.5mm. Main functions compatible with SIM7020 here. Bluetooth function available to use, also lead out antenna connector R3 RTU version retired. Sim800C documentation please see on this page.
