Standard Horizon GM29 manual Main Features and Services, Gmsk

2.GM29 MODEM

2.4Main 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.

GM29	GSM900	E-GSM900	GSM1800
Frequency Range (MHz)	TX: 890-915	TX: 880-890	TX: 1710-1785
	RX: 935-960	RX: 925-935	RX: 1805-1880
Channel spacing	200kHz		200kHz
Number of channels	173 carriers *8 (TDMA)		374 carriers *8 (TDMA)
	GSM: channels 1 to 124		DCS: channels 512 to 885
	E-GSM: channels 975 to 1023
Modulation	GMSK		GMSK
TX phase accuracy	< 5º RMS phase error (burst)		< 5º RMS phase error (burst)
Duplex spacing	45MHz		95MHz
Receiver sensitivity at	< –102dBm		< –102dBm
antenna connector
Transmitter output power	Class 4		Class 1
at antenna connector	2W (33dBm)		1W (30dBm)

Automatic hand-over between GSM 900 and GSM1800

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.

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