RS232 based GSM/GPRS modem is built using SIM900. It works on frequencies of 850MHz, 900MHz, 1800MHz and 1900MHz. The size of it is compact and is basically designed with RS232 level converter circuitry. Here the baud rate range is 9600-115200.
At initial stage, the modem is in Autobaud mode. The modem has internal TCP/IP stack via GPRS. Also, the modem is good for SMS and transfer of data. Here, only three wires Tx, Rx, GND is present and it also consists of a built in voltage regulator. With the help of simple AT commands, one can read and send SMS.
- Power supply : 9 to 12V DC
- Onboard power ON and network indicator LED
- Onboard DB9 connector for connecting modem directly to computers serial port
- 3 pin male header (TTL) interface for connecting SIM900 directly with microcontroller
- Onboard PWM and ADC channels
- TCP/IP protocol
- Built in RS232 Level Converter (MAX3232)
- Quad-Band GSM/GPRS 850/ 900/ 1800/ 1900 MHz
- Built in Network Status LED
- Built in SIM Card holder.
- Voltage:5V-12V DC
- Baud rate 9600 - 115200 bps
- Quad-Band 850/ 900/ 1800/ 1900 MHz
- Weight: 3.4g
- GPRS multi-slot class 10/8
- GPRS mobile station class B
- Control via AT commands (GSM 07.07 ,07.05 and SIMCOM enhanced AT Commands)
- Dimensions: 24*24*3mm
- Compliant to GSM phase 2/2+ , Class 4 (2 W @850/ 900 MHz) , Class 1 (1 W @ 1800/1900MHz)
- Operation temperature: -40°C to +85 °C
- Low power consumption: 1.0mA(sleep mode).
Specifications for Data
- Non transparent mode, USSD, PPP-stack
- PBCCH support , GPRS class 10: max. 85.6 kbps (downlink) ,Coding schemes CS 1, 2, 3, 4
- CSD up to 14.4 kbps
Specifications for SMS via GSM/GPRS
- SMS cell broadcast , Text and PDU mode