User's Manual

GM28 INTEGRATOR’S MANUAL

LZT 123 7468 P1A

2. GM28 Modem

2.1 Description

The dual band GSM 850/1900MHz GM28 is a GSM/GPRS serial

modem. The modem is a powerful and flexible device that can be used

in a wide range of telemetry and telematics applications that rely on the

remote exchange of data, voice, SMS or faxes via the GSM cellular

network.

Small and lightweight, the GM28 has standard connectors and an

integral SIM card reader making it easy and quick to integrate. As well

as providing a standard RS232 serial communication interface the

GM28 also has an audio interface allowing an analogue handset to be

connected. When the GM28 is integrated into an external application, a

wireless communications system is created.

A typical end-to-end system consists of a micro controller in an external

application communicating, via the GM28 modem, with a remote

terminal or host using the GSM network. The micro controller uses a set

of AT commands to control the modem, and to set up the end-to-end

communications link, via its 9-way RS232 serial interface.

GM28 serial modems are intended to be used by manufacturers, system

integrators, application developers and developers of a wide range of

equipment and business solutions, typically in the following fields:

• Security and alarms

• Vending

• Monitoring and control

• Utilities

• Fleet Management

2.2 Highlights

• Dual band, GSM 850/1900MHz, GSM/GPRS serial modem

• Flexible plug-and-play device

• Data: GPRS, HSCSD, CSD, SMS

• Voice: full rate, enhanced full rate, half rate

• SMS: mobile-originated, mobile-terminated, cell broadcast

• Fax: Group 3, Classes 1 & 2

• RS232 9-way serial interface

• 5V - 32V d.c. input

• 4-wire audio connection

• Antenna connection (FME male)

• FCC and PTCRB approved