6 A1120/40 Users Manual - Chapter 3
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3 GSM MODEMS GENERAL INFORMATION
GSM (Global System for Mobile) Communications Modems are ideally suited for use in remote
areas where it is not practical to connect to a PSTN telephone network. The modems can be
used in any area that provides GSM coverage.
Two types of GSM modems have been developed for use with the A1120/40 meter:
Technolog A1120/40 GSM Cello Modem
ASL A1120/40 GSM Modem
The modems have been custom designed for use with the A1120/40 meter and can be installed
beneath the meter terminal cover.
GSM modems can be used with the Service provider of your choice.
Meters can be multi-dropped if required (See Section 4.2.1 for multi-drop Installation).
About the SIM
The SIM Card must be provided by the by the Network Service Provider (O2, Orange, Vodafone
etc) with the following settings:
Data enabled
Air baud rate: 1200 - 9600 (the SIM baud rate must be configured to match the meter serial port
baud rate)
Transparent (no error correction) or non-transparent (error correction)
The preferred settings for the A1120 are - 9600 baud, non-transparent
SIM security pin disable
It is a requirement that the SIM Card Pin Security Number for all types of GSM modem
is disabled on installation. If the pin security number is enabled and the modem is
powered down, a site visit will be necessary to re-enter the pin number.
Transmission speeds (all modems)
1200 baud 2400 baud 4800 baud 9600 baud
Error checking
The GSM system allows full verification of all data received when configured in non-
transparent mode.
Antenna
There is a wide range of antennae, each with their own characteristics for use with
GSM modems. It is therefore important to choose an antenna most suitable for your
installation.
© Elster Metering Limited - M181 001 4A - 5/2007 DRAFT
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