What is "Direct Working"?

The term "Direct Working" refers to a set of DRY relay contacts in a PABX that close whilst a ring signal is being received (usually on an incoming exchange line call) and are used to trigger an external alarm or other device. The PABX contacts are wired to screw terminals 3 & 10 in the Universal Alarm.

It's important to make sure that the contacts are DRY and do not supply any voltage to the alarm. Possible damage to alarm components may be caused by a DC or AC voltage being applied across screw terminals 3 & 10.