M5Stack GSM Module SIM800L with MIC & Headphone Jack
SIM800L is a cellular phone module, integrated SIM800L, a GSM/GPRS module, only cpmpatible with 2G network. if you want to integrate a cellular module into your design with vioce, text and SMS, this hand-solderable module is pretty nice!
M5Stack Fire has occupied GPIO16 / 17 to connect with the PSRAM by default, it's conflict with TXD / RXD (GPIO16, GPIO17) of SIM800L module. Therefore, when using the SIM800L module with the M5Stack Fire, you might have to cut the TXD and RXD from SIM800L module and wire fly to another set of UART pin