M Glossary Terms - M M.O.V. Metal oxide varistors – a device used at the load to reduce electronic kickback and electrical noise. Close Macs Maximum adjacent cut specification used in pinning cylinders. Close Magnetic Stripe Card An access card with a band of magnetic material that must be inserted into a magnetic stripe reader in order to gain access or complete a transaction. Often used for credit and debit cards, magnetic stripe technology is less secure than today’s credential technologies. Close Main Arm The part of a double lever arm that connects directly to the pinion of the closer. Close Maintained Contact Switches which will remain in the same position until being manually moved to another position. Similar to a light switch. Close Manual Flushbolt A mortise bolt installed near the top and bottom of the inactive leaf of a pair of doors in which the bolts are manually extended or retracted into or out of the header or sill by means of a lever. Close Master Key A key that operates all of the master keyed cylinders in a group, with each cylinder usually having its own change key. Close Master Keyed A group of cylinders combinated in such a way that all may be operated by their own change key and a MASTER KEY. Close Master Keyed System (LEVEl 2 SYSTEM) – A key system that has two or more levels of keying. Close Master Keying Preparation of a cylinder to operate with keys of differen tlevels of access. Close Master Ring Cylinder A cylinder which offers a wider range of keying. Close Meeting Stile The vertical edge of a door, when used in a pair, that is adjacent to the other door of the same pair. Close Milli Amp One thousandth (1/1000) of an Ampere. Close Mobile Access The use of a mobile device, such as a smartphone, tablet or wearable, to gain access to secured doors, gates, networks, services and more. Close Mogul Cylinder A very large pin tumbler cylinder whose pins, springs, key, etc. are also proportionally increased in size. It is typically used in prisonl ocks. Close Momentary Contact Switch contacts that remain in one position only while being acted upon. Similar to a door bell push button. Close Mortar Box Used to protect the area and/or wiring behind electrical components. Located in the same frame. Close Mortise Lock A lock that is designed to install into a mortised pocked in the door edge, rather than being applied to the doors surface. The lock trim then bolts into or through the lock case and door face. Close Mortise Preparation Reinforcing, blocking, drilling and/or tapping for hardware that requires such a preparation in a door or frame. Close Mounting The method by which the closer is attached to the door and frame. Close Mullion A fixed or removable vertical member that divides a door opening and provides a latch surface for a pair of rim exit devices. Close Multimeters A tool used to determine voltage, amerage, and resistance in a circuit. Close Multiple Backcheck Location Valve valve which can change where backcheck occurs. Close Multiplex Key System A series of different key sections which may be used to expand a master key system by repeating bittings on additional key sections. The keys of one key section will not enter the keyway of another key section. Close Multi-Point Hold Open Infinite hold-open points from zero up to a maximum degree of the opening. Close Multi-Section Key Blank A key section which enters more than one, but not all keyways in a multiplex key system. Close