User's Manual

Chapter 8 – SocketModem GPRS (MTSMC-G)
Multi-Tech Systems, Inc. Universal Socket Hardware Guide for Developers (S000342D) 116
Application Notes
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 for SIM functionality.
Five Signals Are Available:
SIMVCC: SIM power supply.
SIMRST: reset.
SIMCLK: clock.
SIMDATA: I/O port.
SIMPRES1 SIM card detect.
RF Interface
Radio Characteristics
GSM 850 EGSM 900 GSM 1800 GSM 1900
Frequency RX 869 to 894 MHz 925 to 960 MHz 1805 to 1880 MHz 1930 to 1990 MHz
Frequency TX 824 to 849 MHz 880 to 915 MHz 1710 to 1785 MHz 1850 to 1910 MHz
RF Power Stand 2W at 12.5% duty cycle 2W at 12.5% duty cycle 1W at 12.5% duty cycle 1W at 12.5% duty cycle
Impedance 50 ohms
VSWR <2
Typical Radiated Gain 0 dBi on azimuth plane
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