CyberResearch® Serial Communications

COMT 366 Series

1.0 General Description

The COMT 366 converter provides a convenient method of interfacing EIA-232-based equipment with an RS-485 network using a half-duplex, single twisted-pair transmission protocol. The COMT 366 provides the capability for a high-speed, low cost, local area network. Up to 32 users can be supported at rates up to 38.4K Baud and total separations of 6,000 feet. The LCD feature assists with installation and troubleshooting.

1.1 The LCD

Your COMT 366 product incorporates an LCD display designed to provide meaningful information to the user. It will assist in the initial installation and check out; thereafter it can be used as a performance monitor. In the case of a system problem, it provides information as to the status of the local link.

The logo shown on the LCD display indicates the unit is powered. For power-stealing devices such as a converter, it is an indication that sufficient power is being applied to operate the device. The LCD display uses less than 1 milliWatt of power.

The data display on the LCD consists of graphical representations of TD (Transmit Data) and RD (Receive Data). Each of these signals is displayed the way a bit-change waveform would appear on an oscilloscope. Ordinarily, TD and RD are low or a minus voltage in the quiescent state. When data is transmitted, the transmit signal is brought high to a positive voltage. These two signal states are displayed on the LCD by either a low segment or a high segment. The low segment represents the minus voltage (the mark condition) while the upper segment represents a positive voltage (the space condition). The vertical bar connecting the lower segment to the upper segment is always on when power is applied.

CyberResearch, Inc.

1

25 Business Park Drive

P: (203) 483-8815; F: (203) 483-9024

Branford, CT USA

www.cyberresearch.com