CyberResearch RS-232 - Manual (Page 10)

COMT 366 Series CyberResearch
®
Serial Communications
2 ©Copyright 2001 CyberResearch, Inc.
If the transmit signal is in the quiescent state (continuously low) only the lower segments
and the vertical bar will be illuminated. This indicates a constant negative state. If the
transmit or receive inputs to the device were streaming, i.e., in the positive mode
continuously, the LCD display would show the vertical segment and the upper segments
only. For those cases where there is valid data transmission, both the upper and lower
segments will be displayed simultaneously. A variation in display intensity between
lower and upper segments will give the user a perception of the amount of data being
transmitted.
The LCD display also shows the status of the following control signals: CTS, RTS, DSR,
DCD, and DTR. These signals are displayed as mnemonic symbols, composed of three
letters each, on the bottom line of the display. The presence of the three-letter mnemonic
indicates that the respective control signal is high or positive. If the control signal is
negative, the three-letter mnemonic is not displayed. For most full-duplex data-only
converters, CTS and RTS are connected together while DSR, DCD, and DTR are
connected together. The LCD display will help verify correct operation.