Specifications
PART 2 – Cellular SocketModems Chapter 2 – SocketModem Cell & SocketModem iCell GPRS
Multi-Tech Systems, Inc. Universal Socket Hardware Guide for Developers (S000342P) 66
Application Notes
LED Interface
The LED signal is used to indicate the working status of the SocketModem.
LED 1 – Link Status – Available for G2, G2-V, G2-IP, and G2-GP Builds
LED 1 Signal
Link Status LED
OFF
Download mode or switched OFF
ON
Continuously lit
Switched ON (not registered on the network)
Blinking
Switched ON (registered on the network)
LED 2 – Heartbeat LED – Available for G2-IP and G2-GP Builds
LED 2 Signal
Heartbeat LED
OFF
No power to the unit
Blinking
The unit is functioning
RF Performances
RF performances are compliant with the ETSI recommendation 05.05 and 11.10.
Note: The following statistics are subject to change due to pending test results.
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 a UFL standard type. See Chapter 1 for Antenna System details.
Microphone Inputs
Note: For Voice Build Only.
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