Harris Intraplex STL-160 Series Installation & Operation Manual page 165

6-Testing & Troubleshooting
● No transmit output (TX OUT indicator light off)
● Alarm at one or more channel modules (module's alarm indicator light is on or module is in alarm
state)
The ALARM indicator light is also on briefly when power is first applied to the system.
6.6.5.3 Alarm Cut-Off (ACO) Switch
The alarm cut-off (ACO) switch is located near the front of each power supply module (Figure 6-11).
When the ACO switch is off, the alarm and alert relays respond to alarm and alert conditions.
However, when the ACO switch is on, these relays are disabled; that is, they are forced into their
normal (non-alarm) positions.
You can use the ACO switch on an ACS-160 Series multiplexer to silence a local alarm once this
multiplexer has been identified as the source of the alarm. After correcting the condition that produced
the alarm or alert, be sure to return the ACO switch to its off position.
The 1RU shelf has no power supply redundancy capability. When an Intraplex 3RU multiplexer is
equipped with a redundant power supply, the relays on both the main and redundant power supplies
respond to alarm and alert conditions, ensuring that alarm/alert monitoring continues even while one
or the other supply is removed. Because the corresponding relay contacts on the main and redundant
supplies are connected in parallel, the ACO switches on both must be on to activate the alarm cut-off.
Harris Corporation
Intraplex Products
ACS-160 Series & STL-160 Series T1 Mux Installation & Operation
Version 2.11, August 2011
6-21