channel for control signals.
ISO
International Standards Organization: based in Geneva, Switzerland. It is responsible for promoting global trade of 90 member countries and establishing a wide range of voluntary standards including those pertaining to networking. The ISO developed the OSI reference model.
ITU
United Nation’s specialised agency for telecommunications. The ITU holds periodic conferences at which telecommunications issues of global importance are discussed. The main conferences are the World Radio Conference (WRC) and the World Telephone and Telegraph Conference (WTTC). It is the ITU which
Kbps
Kilobits per second: standard measurement of data rate and transmission capacity. One kbps equals 1000 bits per second.
Portion of the electromagnetic spectrum in the
LAN
Local Area Network. A network connecting computers in a relatively small area.
L-band
The frequency range from 0.5 to 1.5 GHz. Also used to refer to the 950 to 1450 MHz used for mobile communications.
LCD
Liquid Crystal Display. LCD displays utilize two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light.
LED
Light Emitting Diodes. LEDs are special diodes that emit light when connected in a circuit. They are frequently used as pilot light in electronic appliances to indicate whether the circuit is closed or not.
LLC
Logical Link Control. Data link layer sublayer defined by the IEEE. The LLC sublayerhandles error control, flow control, framing, and
LLC SNAP
Subnetwork Access Protocol. An Internet protocol that operates between a network entity in the subnetwork and a network entity in the end system. The SNAP entity in the end system makes use of the services of the subnetwork and performs three key functions: data transfer, connection management, and QoS selection.
LNB
Low Noise Block Amplifier/Converter. Hardware device for converting and amplifying a band of satellite signals from a high frequency (usually GHz) into lower IF frequency (usually MHz). The LNB is mounted in the focal spot of a satellite dish.