A prebuilt GPRS module is used to allow the telematic device to send current GPS data in the form of HTTP requests to the central server. This device also allows communication between the driver of the vehicle and the customer ina safe and efficient manner.
The SIM300 GPRS module has been chosen for this project, Produced by SIMCom, the device uses an RS232 data link for control and communications between the module and telematic device supports the AT command set outlined by The European Telecommunications Standards Institute (ETSI).
The GPRS device is controlled using a Bash script that constructs AT control sequences based on its calling arguments, the script then passes these AT commands onto a simple C program that sends a given command and waits for the response from the device.
GPRS module specification
|Power Supply:||3.4 - 4.5 V|
|Frequency bands:||Tri-band: EGSM 900, DCS 1800, PCS 1900|
|Transmitting power:||2 W using EGSM 900|
|1 W Using DCS 1800 and PCS 1900|
|Data Transfer (GPRS)||Downlink 85.6 kbps (max)|
|Uplink 42.8 kbps (max)|
|Supports Password Authentication Protocol (PAP) used for PPP connections|
|Integrates the TCP/IP protocol|
|Supports 1.8 and 3 V SIM card|
|Serial port control interface|
|SIM application Toolkit|