This is a wireless communication module, integrated M8321 module that released by China Mobile, provided TD-LTE/FDD-LTE/WCDMA/TD- SCDMA/GSM/GPRS/EDGE Frequency Band and LCC+LGA package type. It has integrated plentiful Internet protocols, field standard interface, and functions, supported WindowsXP,Windows7,Windows8,Windows10,Linux and Android USB driver. In the LTE-4G module scheme, we added more hardware resources, 1 reserved speaker solder panel, 3 LEDs, exported USB interface, double antennea allowed. M8321 is 4V power input, so in the hardware of LTE-4G module, we added a Bidirectional Voltage-Level Translator (TXS0104E), to switch the power supply to 4V.
In telecommunication, Long-Term Evolution (LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/EDGE and UMTS/HSPA technologies. It increases the capacity and speed using a different radio interface together with core network improvements.
M5Stack Fire has occupied GPIO16 / 17 to connect with the PSRAM by default, it's conflict with TXD / RXD (GPIO16, GPIO17) of LTE module. Therefore, when using the LTE module with the M5Stack Fire, you might have to cut the TXD and RXD from LTE module and wire fly to another set of UART pin