SIM900A GSM/GPRS Modem-RS232 is built with Dual-Band GSM/GPRS engine- SIM900A works on frequencies 900/ 1800 MHz. The Modem is coming with RS232 interface, which allows you connect PC as well as a Microcontroller with RS232 Chip(MAX232).
The baud rate is configurable from 9600-115200 through AT command. The SIM900A GSM Modem is having internal TCP/IP stack to enable you to connect with internet via GPRS. It is suitable for SMS, Voice as well as DATA transfer application in M2M interface.
Command Set : AT Command
The onboard Regulated Power supply allows you to connect wide range unregulated power supply. Using this modem, you can make audio calls, SMS, Read SMS, attend the incoming calls and internet etc through simple AT commands.
This board requires external power supply of ~12V and can draw up to ~2A of current at its peak.
It has two LED indicators as :
POWER ON LED: It shows that the Modem is getting powered and is switched on.
NETWORK LED: This network LED blinks when the modem is communicating with the radio network.
When modem is powered up, network LED blink every second and after network registration it will start to blink after every 3 seconds. This shows that the modem is registered with the network.
To test modem, connect board serially to PC and send “ATE0” or “AT” through serial terminal. If “OK” response is received from the modem, then it means all is well.
GSM/GPRS Modem Features
- High Quality Product (Not hobby grade)
- Dual-Band GSM/GPRS 900/ 1800 MHz
- RS232 interface for direct communication with computer or MCU kit
- Configurable baud rate
- Wire Amntenna ( SMA connector with GSM Antenna Optional )
- SIM Card holder.
- Built in Network Status LED
- Inbuilt Powerful TCP/IP protocol stack for internet data transfer over GPRS.
- Normal operation temperature: -20 °C to +55 °C
- Input Voltage: 12V DC