User's Manual

2. GM29 MODEM
17
LZT 123 7361 R1A
2.4 Main Features and Services
The modem performs a set of telecom services (TS) according to GSM
standard phase 2+, ETSI and ITU-T. The services and functions of the
modem are implemented by issuing AT commands over the RS232
serial interface.
2.4.1 Types of Mobile Station
The GM29 is a dual band serial modem with the GSM radio
characteristics shown in the table below.
2.4.2 Short Message Service
The modem supports the following SMS services:
• Sending; MO (mobile-originated) with both PDU (protocol data
unit) and text mode supported.
• Receiving; MT (mobile-terminated) with both PDU and text mode
supported.
• CBM (cell broadcast message); a service in which a message is sent
to all subscribers located in one or more specific cells in the GSM
network (for example, traffic reports). This feature is network
dependent.
• SMS STATUS REPORT according to GSM 03.40.
• SMS COMMAND according to GSM 03.40.
The maximum length of an SMS message is 160 characters when using
7-bit encoding. For 8-bit data, the maximum length is 140 characters.
The modem supports up to 6 concatenated messages to extend this
function.
GM29 GSM900 E-GSM900 GSM1800
Frequency Range (MHz) TX: 890-915
RX: 935-960
TX: 880-890
RX: 925-935
TX: 1710-1785
RX: 1805-1880
Channel spacing 200kHz 200kHz
Number of channels 173 carriers *8 (TDMA)
GSM: channels 1 to 124
E-GSM: channels 975 to 1023
374 carriers *8 (TDMA)
DCS: channels 512 to 885
Modulation GMSK GMSK
TX phase accuracy < 5º RMS phase error (burst) < 5º RMS phase error (burst)
Duplex spacing 45MHz 95MHz
Receiver sensitivity at
antenna connector
< –102dBm < –102dBm
Transmitter output power
at antenna connector
Class 4
2W (33dBm)
Class 1
1W (30dBm)
Automatic hand-over between GSM 900 and GSM1800