CTI Products CIB Comparator Interface - Manual (Page 11)

CIB Hardware Reference Theory of Operation
CTI Products, Inc.
68-10854-135
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If the comparator detects that a receiver has failed, then it drives the FAIL input to
the CIB. Again, the CIB detects this FAIL input and sends a message to the User
Interface Module so that the user can see that the receiver has failed.
From the operator station, the user can generate FORCE VOTE or DISABLE
commands for each receiver in the system. The User Interface Module detects
these commands and sends them to the CIB. The CIB then drives the appropriate
VOTE or DISABLE outputs to the comparator, telling it which receivers were
force voted or disabled.
3.4 Bi-directional I/O Signals
The CIB provides two input/output lines per receiver (VOTE and DISABLE) that
allow both monitoring and control of the signal (Figure 2 shows the equivalent
circuit for the input/output lines). If a receiver is disabled at the comparator, the
CIB will send a message to the User Interface Module so that the disabled
indication for the receiver can be shown at the operator station. Because the
comparator is now driving the input of the bi-directional DISABLE line, the
receiver cannot be re-enabled from the operator station. Pressing a disable button
on the operator station will have no affect on the receiver. If the disable button is
pressed multiple times, you could end up with the disable output latched on
(depending upon how many times the disable button is pressed). If this happens,
when the receiver is re-enabled at the comparator, the operator station will still
show the receiver being disabled when in fact the receiver is enabled. If you re-
enable a receiver at the comparator and the Disable indication remains on, re-
enable the receiver through the MCN system.
3.5 Transmitter Status Monitoring and Control
The MCN family includes an auxiliary module that allows monitoring and control
of transmitter sites. This module is called a TSAM Interface Module, or TIB, and
it interfaces between the CIB and CTI Product’s Transmitter Steering Audio
Matrix (TSAM) device (see reference 2). The CIB passes FORCE VOTE
information to the TIB to control or select the active transmitter. The TIB passes
transmitter information to the CIB so that the active transmitter can be displayed
with a User Interface Module that supports display of transmitter status, such as a
HIB with MCNRCD running on a PC.
The CIB will provide this transmitter monitoring and control only if its transmitter
monitoring enable switch, OPTION switch 3, is in the UP position. If this switch
is in the DOWN position, all transmitter monitoring and control is disabled.
The CIB and TIB communicate over the MCN network so no special wiring is
required between the modules.