Raspberry PI GSM Add-on is customized for Raspberry Pi interface based on SIM900 quad-band GSM/GPRS module. AT commands can be sent via the serial port on Raspberry Pi, thus functions such as dialing and answering calls, sending and receiving messages and surfing on line can be realized. Moreover, the module supports powering-on and resetting via software.



  • Quad-Band 850/ 900/ 1800/ 1900 MHz
  • GPRS multi-slot class 10/8GPRS mobile station class B
  • Compliant to GSM phase 2/2+Class 4 (2 W @850/ 900 MHz)
  • Class 1 (1 W @ 1800/1900MHz)
  • Control via AT commands (GSM 07.07 ,07.05 and SIMCOM enhanced AT Commands)
  • Low power consumption: 1.5mA(sleep mode)
  • Operation temperature: -40°C to +85 °C



PCB size 73.8mm X 70mm X 1.6mm
Input voltage  5V
Interface  UART
Baud rate 9600 (default)


Electrical characteristics

Parameter Min. Typical  Max.  Unit
Supply voltage - 5 5.5 VDC
Current consumption (average)  - 500 - mA
Instantaneous current consumption - - 2 A




Raspberry PI interfaces

Raspberry PI Pin N.O.  Pin name  Pin of SIM900 Module Description
11 GPIO0 SIM900-PWERKEY  Powering-on key via software
12 GPIO1 SIM900-RST  Resetting key via software
13 GPIO2 -  
15 GPIO3 -  
16 GPIO4 -  
18 GPIO5 -  
22 GPIO6 -  
7 GPIO7 -  
3 SDA0 -  
5 SCL0 -  
24 CE0 -  
26 CE1 -  
19 MOSI -  
21 MISO -  
23 SCLK -  
8 TXD SIM900_RX Receiving end for SIM900 serial port
10 RXD SIM900_TX  Sending end for SIM900 serial port
2 +5V -  
1 +3.3V -  
6 GND -  

Other interfaces

Pin name Description
DR  Receiving end for SIM900 debugging serial port
DT Sending end for SIM900 debugging serial port
VBAT SIM900 supply 4.2V
G Ground
V Electronic brick interface supply pin 3.3V



  • PWR

Power: When there is normal supply to the board, the indicator keeps on.


SIM900 status: When SIM900 works normally, the indicator keeps on.

  • NET

SIM900 network status: used to indicate network status, the working status of the indicator is as below:

Network indicator status  SIM900 working status
OFF SIM900 does not work
64ms on/800ms off SIM900 does not find network
64ms on/3000ms off  SIM900 registers the network
64ms on/300ms off  GPRS communicates




SIM900 powering-on key: Keep pressing the key for more than 1 second, SIM900 will be powered on; keep pressing the key for more than 1 second after the board is powered on, SIM900 will be powered off.

  • SIM900-RST

SIM900 resetting key: press the key, SIM900 will be reset.



  • The module does not support hot swapping.


Packing List

  • Raspberry PI GSM Add-on x 1
  • Antenna x 1



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  • Brand: Itead Studio
  • Product Code: IM131224002
  • Availability: 7 - 10 days
  • 44.58€

  • Ex Tax: 36.84€