Dtr; Dsr; Rts; Xmt - Control Data Corporation INFORMATION SYSTEMS TERMINAL II Hardware Maintenance Manual

DTR
The Data Terminal Ready indicator is normally lit when the
terminal is on.
DSR
The data set ready (DSR) indicator follows the state of the
DSR signal as provided at the terminal's PLATO interface
connector or as provided by the internal modem. This
indicator will be lit when using the internal modem or when
connected to a functioning external modem. It will always
be lit when using the interface identified in table 3-1.
RTS
The Request to Send indicator is always lit when not in
test mode.
RCV
The Received Data indicator monitors the Received Data line
after being ANDed with the Carrier Detect and Data Set
Ready (when the RS-232 interface is used) or the long line
receiver (when the long line interface is used).
The indicator is lit when the input signal is in the space
(logical 0) condition, and off in the mark (logical 1)
condition.
XMT
I
The Transmitted Data indicator monitors the output of the
transmit shift register before the signal gets to the
RS-232-C or long line drivers. It is lit in the space
(logical
0)
condition and off in the mark (logical 1)
condition.
ERR
The Error indicator indicates to the user that some kind of
error condition has been detected by the controller. See
section
6
in this manual for error codes and their
definitions.
2-6
82100083 D