DEFINITY Made Easy Tools
Issue 2, November 2000

DEFINITY Hardware

Alarm connections

The system you are upgrading may use more than 1M and 1m alarm-monitor appearances. If so, use one of the following methods to redistribute the alarm-monitor appearances:

Redistribution methods

• Distribute the alarms to the AUXILIARY connector on an R7si EPN.


• Parallel the alarms to the connections shown in the table above.


• "Gang" the alarms so that several external devices share the same appearance.



Note that:

Results of ganging method

• When several external devices are ganged to the same appearance, each device loses its individual identity.


• An alarm on a shared appearance denotes only that one of several devices reported a problem. Subsequent maintenance effort is needed to determine which device reported the problem and the nature of the problem.


• The control circuit pack behind the AUXILIARY connector detects external alarms with a ground-detector chip. Therefore, if you gang several external devices, every device must be able to return a true relay ground closure to the AUXILIARY connector. (Alternatives such as a TTL low driver are inadequate.)