Latch : The locking of a circuit by means of a holding contact; used in relay logic when a momentary initiation is required.
Light emitting diode (LED) A diode, a solid-state device, that gives off virtually heatless colored light when electric current is passed through it. LED’s are very efficient and long lasting and are often used for digital readouts and annunicators. Common colors include red, green, and amber.
Line drop A voltage loss occurring between any two points in a power or transmission line. Such loss or drop is due to the resistance, reactance, or leakage of the line. (also referred to as line loss).
Line voltage The voltage existing in a main cable or circuit, such as a wall outlet.
Listed Refers to equipment or material included in a list states that the equipment or material met appropriate standard or has been treated for and suited to a specific application.
Load Any device that consumes electrical power; the amount of power required for operation or circuit or device.
Load Rating A control specification outlining the type of load the minimum (min) the maximum (max) currents ands the voltage.
Local Alarm A visual or audible signaling device located at a monitored door, window or other opening.
Lock Status Sensor (LSS) Relay type to operate the LED with an SPDT switch to indicate low voltage and tampering of the lock face locally or to a remote monitoring location.
Lattice Techniques : Lattice Techniques use security designations to determine access to information.
Layer 2 Forwarding Protocol (L2F) : An Internet protocol (originally developed by Cisco Corporation) that uses tunneling of PPP over IP to create a virtual extension of a dial-up link across a network, initiated by the dial-up server and transparent to the dial-up user.
Layer 2 Tunneling Protocol (L2TP) : An extension of the Point-to-Point Tunneling Protocol used by an Internet service provider to enable the operation of a virtual private network over the Internet.
Least Privilege : Least Privilege is the principle of allowing users or applications the least amount of permissions necessary to perform their intended function.
Legion : Software to detect unprotected shares.
Lightweight Directory Access Protocol (LDAP) : A software protocol for enabling anyone to locate organizations, individuals, and other resources such as files and devices in a network, whether on the public Internet or on a corporate Intranet.
Link State : With link state, routes maintain information about all routers and router-to-router links within a geographic area, and creates a table of best routes with that information.
List Based Access Control : List Based Access Control associates a list of users and their privileges with each object.
Loadable Kernel Modules (LKM) : Loadable Kernel Modules allow for the adding of additional functionality directly into the kernel while the system is running.
Log Clipping : Log clipping is the selective removal of log entries from a system log to hide a compromise.
Logic bombs : Logic bombs are programs or snippets of code that execute when a certain predefined event occurs. Logic bombs may also be set to go off on a certain date or when a specified set of circumstances occurs.
Logic Gate : A logic gate is an elementary building block of a digital circuit. Most logic gates have two inputs and one output. As digital circuits can only understand binary, inputs and outputs can assume only one of two states, 0 or 1.
Loopback Address : The loopback address (127.0.0.1) is a pseudo IP address that always refer back to the local host and are never sent out onto a network.