Specifications

Chapter 8 – SocketModem GPRS (MTSMC-G)
Multi-Tech Systems, Inc. Universal Socket Hardware Guide for Developers (S000342C) 118
Application Notes
SocketModem GSM/GPRS Interfaces
• Flashing LED
• SIM Interface
• RF Interface
Flashing LED Interface
The flashing LED signal is used to indicate the working mode of the SocketModem.
LED and SocketModem Status
Signal SocketModem Status
OFF Download mode or switched OFF>
Continuously lit Switched ON (not registered on the network) ON
Flashing Switched ON (registered on the network)
SIM Interface
The internal SIM interface of the SocketModem supports 3V SIMs only.
Note: This interface is fully compliant with GSM 11.11 recommendations concerning the SIM
functionality.
Five Signals Are Available
SIMVCC: SIM power supply.
SIMRST: reset.
SIMCLK: clock.
SIMDATA: I/O port.
SIMPRES1 SIM card detect.
RF Interface
The impedance is 50 Ohms nominal.
RF Connector
The RF connector is MMCX standard type. An antenna can be directly connected through
the mating connector or using a small adapter.
RF Performances
RF performances are compliant with the ETSI recommendation 05.05 and 11.10.
The main parameters are:
Receiver Features
• EGSM Sensitivity : < -104 dBm
• GSM 1800/GSM 1900 Sensitivity : < -102 dBm
• Selectivity @ 200 kHz : > +9 dBc
• Selectivity @ 400 kHz : > +41 dBc
• Dynamic range : 62 dB
• Intermodulation : > -43 dBm
• Co-channel rejection : + 9 dBc
Transmitter Features
• Maximum output power (EGSM) : 33 dBm ± 2 dB
• Maximum output power (DCS/PCS) : 30 dBm ± 2 dB
• Minimum output power (EGSM): 5 dBm ± 5 dB
• Minimum output power (DCS/PCS): 0 dBm ± 5 dB
• H2 level : < -30 dBm
• H3 level : < -30 dBm
• Noise in 925 - 935 MHz : < -67 dBm
• Noise in 935 - 960 MHz : < -79 dBm
• Noise in 1805 - 1880 MHz : < -71 dBm
• Phase error at peak power : < 5 ° RMS
• Frequency error : ± 0.1 ppm max