Glossary

Term	Description
Output	A device on a panel which sends a signal or provides information to the field devices to activate controls. Usually a relay which has dry contacts (not supplying power) only switching power provided to it.
Passive Infrared Detector (PIR)	A motion sensing device, often used for intrusion detection systems, can also be used as a REX to unlock a door as someone wishing to egress approaches.
PLC	Programmable Logic Controller: a small industrial computer that controls one or more hardware devices.
Proximity	A common access card technology, proximity uses radio frequency to communicate between a card or tag and a reader without physical contact.
PSIM	Physical Security Information Management
Rated voltage	The maximum voltage at which electric component can operate for extended periods without undue degradation or safety hazard.
Reader	A device that obtains data from an access credentials (card, tag, etc.) and send the data to a controller for an access decision. (Some units combine reader and keypad in one device.)
Relay	An electrically controlled device that opens and closes electrical contacts to effect the operation of other devices in the same or another electrical circuit.
Resistor	A circuit element whose chief purpose opposes the flow of current, causing a decrease in voltage.
REX	A REX (request to exit) is used to determine if someone is waiting at the door. It can be ultrasonic, infra-red or simply a button. It is usually installed on the inside of the door and is used to automatically unlock the door if someone wants to leave a building. In most cases, a badge is not required to leave a building (although in some circumstances this may not be true). A REX sensor would then let the panel know that someone wants to leave, and react by the panel unlocking the door for them if programmed so.
Routing Level	A Routing Level is Computer based or workstation based. A Routing Level determines whether or not Events or Alarms are sent to specific computers. Different events may not be important to an operator across the building or campus from the operator. A Routing Level provides the computer to filter out the events that are important to it.
RTU	A generic term that represents any equipment or software with which Intelli-Site integrates. A card reader, a DVR, a RFID reader, are all examples of RTUs.
RTUs	More than one RTU, a generic term that represents any equipment or software with which Intelli-Site integrates. A card reader, a DVR, an RFID reader, are all examples of RTUs.
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 lock bolt. When electricity is applied, a mechanical motion is obtained that moves the bolt.
SP	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.
Spike	A momentary increase in electric current Spikes can damage electronic equipment.
TCP/IP	(Transmission Control Protocol/Internet Protocol) A communications protocol developed under contract from the U.S. Department of Defense to internetwork dissimilar systems.TCP/IP is the protocol of the Internet and the global standard for local area networks and wide area networks