My quick notes regarding a SIM800L module on an inexpensive SIM800L EVB “SIM800LV2.2” carrier board from eBay. Communicates happily with a computer through a generic USB<>TTL converter, 5V logic levels and 5V power at 9600 baud. Carrier board includes a TTL level shifter and 2 diodes in series to drop the voltage from 5V to ~3.6V.

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