Specifications

Chapter 8 – SocketModem GPRS (MTSMC-G-F4 and MTSMC-G-F4-IP)
Multi-Tech Systems, Inc. Universal Socket Hardware Guide for Developers (S000342I) 121
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>
ON Continuously lit Switched ON (not registered on the network)
Flashing Switched ON (registered on the network)
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
RF Connection and Antenna
The RF connector on the SocketModem GPRS is an MMCX standard type. See Chapter 1 for Antenna System
details.
Microphone Inputs
The MIC inputs are differential ones. They already include the convenient biasing for an electret microphone (0,5 mA
and 2 Volts). This electret microphone can be directly connected on these inputs. The impedance of the microphone
has to be around 2K. These inputs are the standard ones for a handset design.
The gain of the MIC inputs is internally adjusted. The gain can be tuned from 30dB to 51dB. The connection to the
microphone is direct.
MIC2N
MIC2P
C1
C1 = 22pF to 100 pF
33 pF recommended