# COM GSM
>COM GSM RXD/TXD can be connected to M5Stack's UART (TX(0/13/17)RX(5/15/16)) by setting the DIP switch. Since these GPIO in **M5Stack Fire** 16/17 are connected to PSRAM by default, conflicts may occur when using GSM. It is recommended to use any set of UART pins in the remaining two groups.
>The DIP switch on the right is invalid for the GSM module, no need to set.
## Product Features
- Stackable design
- Support SMS text and data transmission
- Independent external power supply
- AT command control
- SIM card type: MicroSIM
- Status signal: two LED indicators (power/network status)
- Power supply voltage: 3.4-4.4V
- Typical power consumption in sleep mode: 0.88mA
- External antenna: SMA antenna 2.5dBi
- Serial communication: UART 115200bps
- Operating temperature range: -40°C to +85°C
- Frequency band:
- Quad-band 850/900/1800/1900MHz
- GPRS multi-slot class 12/10
- GPRS mobile station class B
- data transmission:
- PRS class 12: Maximum 85.6 kbps (uplink/downlink rate)
- Support PBCCH (Packet Broadcast Control Channel)
- Coding scheme: CS 1, 2, 3, 4
- Integrated TCP/IP TCP/IP、UDP、HTTP、FTP protocol
- Support USSD (Unstructured Supplementary Services Data)
## Include
- 1x COM GSM module
- 1x SMA antenna
## Applications
- Remote meter reading system
- Automatic Web Spider SMS-notifier
- Wireless communication
## Specification
| Resources | Parameter |
| Frequency band | GSM/GPRS 850/900/1800/1900MHz |
| Network protocol | TCP/IP/UDP/FTP/HTTP etc. |
| Communication | UART 115200bps |
| Antenna Gain | 2.5dB 1880-1900MHZ/2320-2370MHZ 2575-2635MHZ |
| Net Weight | 40g |
| Gross weight | 75g |
| Module Size | 54*54*13.2mm |
| Package Size | 165*60*36mm |
### PinMap
| M5Stack | TX(GPIO0/13/17) | RX(GPIO5/15/16) | 5V | GND |
| COM GSM | RX | TX | VIN | GND |
## Example
### 1. Arduino
To get complete code, please click [here](https://github.com/m5stack/M5-ProductExampleCodes/tree/master/Module/COMX_GSM)