CyberResearch RS-232 - Manual (Page 12)

COMT 366 Series CyberResearch
®
Serial Communications
4 ©Copyright 2001 CyberResearch, Inc.
3.0 Installation
The COMT 366 is designed to interface EIA-232 with RS-485 equipment. The EIA-232
device can be either a DTE or DCE type device. The DTE/DCE selector switch allows
for reversing Pins 2 and 3 ( TD and RD), thereby eliminating the need for null modem
cables. If the switch is in the DTE position, Pin 2 of the RS-232 connector is an output
for the COMT 366.
The half-duplex nature of RS-485 allows for a Master-Slave configuration. In a network,
the master will poll the slaves through the single twisted pair and request that only one
device access the line at a time.
The COMT 366 can operate at the following Baud rate/distance combinations:
Baud rate: 38.4 K 19.2K 9.6K and below
Distance (ft.) 4000 6000 18000
Two pairs of screw terminals are provided to allow the pass through of the twisted pair.
This simplifies installation of a network. There are internal connections between both
positive and both negative terminals.
The COMT 366 can be interfaced to the network bus in two configurations. However, the
results of both configurations are identical. The first configuration allows for a direct
splice into the bus. The second configuration creates a "T" at the bus and runs a stub of
wire to the unit.