1. INTRODUCTION
1.1 Modem
Overview
IG202T-R38 is a multistandard modem for asynchronous or transparent data transmission in
300-3400 Hz voice band. For lower baud rates it uses binary frequency modulation tech-
niques (FSK), which make it highly immune to interference and noise and permit extensive
voice-band communication link utilization. For higher baud rates it uses QAM modulations
with 4, 8 and 16 constelation points, depending of selected rate.
The modem supports CCITT V.29, R.38A, R.38B, R.37, R.35, V.23, BELL 103, BELL 202
proprietary 2400Bd and Cegelec 1200/600Bd communication standards. Table of
programmable channels (Figure 1.) depicts possible utilization of audio band in FSK mode. In
FSK mode the modem can operate in half or full-duplex, point-to-point or point-to-multipoint
mode, with receive and transmit channels independently set. For V.29 mode, four-wire full/half
duplex is default.
The modem employs advanced Texas Instruments 32-bit DSP technology, thus offering high
service flexibility through programmable features. Modem configuration is performed via
Hayes AT commands on separate DIAG serial port, available at front panel. AT commands
may be initiated from any asynchronous terminal application using RS-232 communication
interface. Additionally, for easy firmware upgrade, a bootstrap loader is provided using the
same DIAG serial port.
IG202T-R38 is designed to be use in SCADA systems mainly based upon power
utilitycommunication networks. Depending on selected mode, it can communicate
through specialized, private or leased lines, radio links and power lines (PLC).
Figure 1.
Table of programmable channels in FSK mode
IG202T-R38 User Manual v1.3
, Rev. date: 16 November, 2009
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