Electrical term for bypassing. In access control it is common to shunt an alarm sensor, such as a door position switch, when a door is about to be opened for valid access or egress.

A term used to describe a switch or relay contact from (1form C), that has a normally open and a normally closed contact with a common connection.

A switch with one moving and one stationary contact, available either normally open (NO) or normal closed.

An electro-mechanical device that operates the lock bolt. When electricity is applied, a mechanical motion is obtained that moves the bolt.

Service Pack - a collection of updates and fixes, called patches, for an operating system. Service packs also often include new features in addition to fixes.

A momentary increase in electric current Spikes can damage electronic equipment.