 Electromagnetic spectrum in the 1GHz region. phone handset closes a wire loop, which is detected at the other Leading edge. The side of a pulse waveform which occurs first in time. The rising amplitude part of a pulse signal. See also Lost calls cleared. A method of operation in which calls which are trailing edge. blocked are either rejected by the network, or the blocked call Leased line. Aline, generally leased from a PTT, which is used to leaves voluntarily. These calls may return at a later time. connect several sites and carry private data. Lost calls delayed. A method of operation in which calls which are Liberisation. Usually refers to the licensing of other telecommuni- blocked remain in the system until they are served. cations operators to carry traffic or provide services. Lost calls held. A method of operation in which calls which are Light emitting diode. A semiconductor diode which emits light blocked are held for a time equal to the average holding time. when conducting current. Glossary of terms 62/27 Loudness rating. Overall (mouth to ear) performance measure of Muldex. A term sometimes used to refer to the combination of a a telephone connection. This is also known as reference equi- multiplexer and a demultiplexer at a time division multiplexer valent. terminal. Also referred to as a muldem. Low pass filter. A filter which allows all frequencies below a Multiframe. Sequence of frames having the position of each frame certain value to pass but attenuates all higher frequencies. identifiable by a multiframe alignment signal, which does not necessarily occur in each multiframe. Multifrequency signalling. A signalling system for inter office sy- Managed object. An abstract view of a physical or logical re- tems in which two of six possible tones are used to encode ten source, which represents its attribute (property) as seen by the digits and five special characters. network manager. Managed objects are accessed via agent Multiframe. A set of consecutive frames. Used in digital trans- processes. 