M

	MAC (Media Access Control)
	A system of rules used to move data from one physical medium to another.
	MAC (A, B, C, D2) (Multiplexed analogue component)
	Colour video transmission system. Subtypes refer to the various methods used to transmit audio and data signals.
	Margin
	The amount of signal in dB by which a satellite videoconference system exceeds the minimum levels required for operation.
	MAX (Media Access Exchange)
	It supports up to 32 host ports or direct Ethernet connections and up to 8 Mbps to the network. It supports multiple applications, including remote LAN access, leased line backup and individual videoconferencing units, as well as connecting videoconference MCUs to the digital dial-up network.
	MBONE (Multicast / Multimedia Backbone)
	A collection of Internet routers that support IP multi-casting. The MBONE is used as a "broadcast" channel on which various public and private audio and video programs are sent.
	Mbps
	Megabits per second
	Modulation
	The process of manipulating the frequency or amplitude of a carrier in relation to an incoming video, voice or data signal.
	Modulator
	A device that modulates a carrier. Modulators are found as components in broadcasting transmitters and in videoconference transponders.
	Multiplexing
	Techniques that allow a number of simultaneous transmissions over a single circuit.
	Multipoint
	Communication configuration in which several terminals or stations are connected. Compare to point-to-point, where communication is between two stations only.
	MCU (Multipoint Control Unit)
	Videoconferencing equipment that allows more than three individual videoconference units to connect together to form a multiparty videoconference session. The MCU uses fast switching techniques to patch the presenters or speaker's input to the output ports representing the other participants.
	Multipoint Videoconference
	Videoconference with more than two sites. The sites must connect via a video bridge. (Compare with point-to-point videoconference.)