The functions associated with accessing a metallic facility for the purpose of testing. MTAU functionality may be embedded within a network element (NE) or may consist of stand-alone equipment. [T1.216-1998]

A potential difference between metallic conductors, as opposed to a potential difference between a metallic conductor and ground.

Communications by the propagation of radio signals reflected by ionized meteor trails. [NTIA]

A radiocommunication service used for meteorological, including hydrological, observations and exploration. [NTIA] [RR]

An Earth exploration-satellite service for meteorological purposes. [NTIA] [RR]

A decimal system of weights and measures based on the meter as a unit of length and the kilogram as a unit of mass.
Note: The modern form of the metric system is the International System of Units (SI). See International System of Units.

A data communications network that (a) covers an area larger than a campus area network and smaller than a wide area network (WAN), (b) interconnects two or more LANs, and (c) usually covers an entire metropolitan area, such as a large city and its suburbs.

A particular type of Terrestrial Beacon System (TBS) that uses GPS-like signals to enable determination of the receiver's position. MBS is included in the LTE Positioning Protocol (LPP) 3GPP TS
3
6. 355 starting with Release 13.

The area around and including a relatively large city and in which substantially all of the message telephone traffic between the city and the suburban points within the area is classified as exchange in one or both directions. [47 CFR Pt.36-A]

Abbreviation for medium frequency.