Schedule Programming of an access control system that automatically locks and unlocks doors, or that performs other functions based on day and time.
Secondary The transformer winding that receives energy by electromagnetic induction from primary. Generally the output of the transformer to the low voltage device.
Security condition sensor (scs) A sensitive crystal relay to operate the LED with an SPOT switch indicate low voltage and tampering of the lock locally or to a remote monitoring location. Primarily used in high security applications.
Security interlock A multidoor system in which doors are normally closed and locked; releasing doors disables the releases for release for all other doors until the first door is closed and relocked (see interlock).
Short An improper connection between current-carrying wire and neutral or ground.
Shunt 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.
Single pole, double throw (SPDT) 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.
Single pole, single throw (SPST) A switch with one moving and one stationary contact, available either normally open (NO) or normal closed.
Solenoid An electro-mechanical device that operates the lockbolt. When electricity is applied, a mechanical motion is obtained that moves the bolt.
Spike A momentary increase in electric current Spikes can damage electronic equipment.
Springlatch A plain latch switch, a beveled latchbolt that is activated by springs.
Standalone In access control, this term usually refers to a device that identifies the user (keypad, reader, etc.) and that makes an access decision. Some standalone units also contain a locking device and/or a power source.
Strike A plate mortised into or mounted on the door jamb to accept and restrain the bolt when the door is closed. In some metal installations of deadlock, the strike may simply be an opening into the jamb.
Switches Devices that make or break (open or close) connections in electrical or electronic circuit. In computing systems they are also used to make selections (the toggle switch, for example, completes a condition jump). Switches are usually manually operated but can also work by mechanical, barometric, hydraulic, or gravitation means.
Switch, maintained A switch that, when activated, maintains its activated position until it is unactivated.
Switch, normally open A switch that, when not energized, is open and does not permit current to flow.
Switch, normally closed A switch that, when not energized, is closed to form a path for current