Overview - Bell 5902 Hardware Manual

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Overview

The model 5902 Bell 202 modem converts RS-232 signal levels to audio tones for transmission over
radios, two wire networks, four wire multi-point networks, and four wire point-to-point networks.
The modem is transformer isolated from the communication system, so it is well suited to
applications which may experience high voltage transients, static discharges, or high common-mode
voltages.
The 5902 modem is compatible with virtually all types of radio transceivers. Radio communication
is facilitated by an isolated radio transmitter key output, and a radio frequency carrier detect input.
The input can be used to inhibit transmission if a radio signal is detected. Each signal can be wired
for active high or active low signals. Configurable carrier detect and loss delays, and RTS/CTS
delays provide high quality communication in a broad variety of environments.
Multi-point telephone and radio applications are protected against inadvertent sustained
transmission through a user selected anti-streaming timer. This feature prevents a continuously
keyed modem from swamping the communication system.
Configuration switches permit adjustment of carrier detection and loss delays, anti-streaming time,
soft-carrier turn-off tones, RTS/CTS handshake timing, and full/half duplex selection. Self test and
adjustment modes facilitate field maintenance.
Two package versions are available. The model 5902 modem is a DIN rail mounted version for
SmartWIRE TeleSAFE Micro16 and SCADAPack controllers. The model 5902SA is a desktop
version for with personal computers and other RS-232 equipment. This manual covers the 5902
modem.
5902 Bell 202 Modem Hardware Manual 5
October 19, 2007