ActiveKEY Modem User Manual Page - 3 - of 5
Classification: GE Public
1.
SCOPE
1.1.
WHAT IT IS
This document describes the data modem used in the ActiveKEY product. The modem will be a PTCRB certified generic
data modem that can be used in other applications beyond the ActiveKEY product. The modem supports SMS and GPRS
data transmission, using the GSM cellular network.
2.
ELECTRICAL COMPONENTS
2.1.
CELLULAR DATA MODEM
The wireless communication for this design is currently handled by an Enfora model GSM-0204 Cellular modem module.
This is a dual cellular band module and is controlled by the main microprocessor and associated GE proprietary firmware.
The cellular data modem circuit was designed for use in the ActiveKEY product and as a stand alone cellular data modem
for universal use in any GE applications requiring digital cellular communication capability.
The module resides on a small circuit board that also contains a precision low noise switching voltage regulator that
maintains the operating voltage of the cellular data modem at 3.6 Volts DC over the entire operating range of a lithium ion
cell from 4.2 Volts DC down to 2.75 Volts DC.
A complete RS232 interface is included in this design and is pinned out to a twenty pin male header with Serial data input,
serial data output, Clear To Send , Request To Send, Data Carrier Detect, Ring signal, Data Terminal Ready and Data Set
Ready.
The twenty pin male header on the PCB provides connection for battery or external power and ground and an output for the
regulated 3.6 Volt supply for use by the ActiveKEY main board or other devices when utilized in the stand alone mode of
operation.
2.2.
ENFORA RADIO
The Enfora module used in the ActiveKEY is the Enabler IIG GSM0204-91 850/1900 HW Ver C, SW Ver 0.7.6, SVN 14,
NAPRD 3.7.1. For more information on the Enfora radio, please refer to the following documents:
Title
Version
Date
Enfora Enabler II-G Integration
Guide GSM0108PB001MAN.pdf
1.03
5/9/06
Enabler-IIG AT Command Set
GSM0107PB001MAN.pdf
1.06
6/29/06
GSM0000AN024 - Enhanced Test
Mode Commands.pdf
1.00
2/20/07
2.3.
RADIO COMMUNICATION
The AT+CPMS command is used to query the Enfora for the number of received messages currently stored in its SIM.
The AT+CMGL command is used to get the Enfora to output a list of received messages stored in the SIM, and their
associated index number (1-25).
The AT+CMGR command reads a specific message from the SIM, accessed by its index number.
The AT+CMGD command deletes a message from the SIM, again, accessed by its index number.