Glossary

A condition where an unintended connection to ground is made through an interfering electrical conductor that causes electromagnetic interference. See also ground loop noise.

Electromagnetic interference that is created when equipment is grounded at ground points having different potentials, thereby creating an unintended current path. Equipment should always be grounded to a single ground point.

GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile), is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation (2G) digital cellular networks used by mobile phones, first deployed in Finland in July 1991.

As of 2014 it has become the default global standard for mobile communications - with over 90% market share, operating in over 219 countries and territories.

2G networks developed as a replacement for first generation (1G) analog cellular networks, and the GSM standard originally described a digital, circuit-switched network optimized for full duplex voice telephony. This expanded over time to include data communications, first by circuit-switched transport, then by packet data transport via GPRS (General Packet Radio Services) and EDGE (Enhanced Data rates for GSM Evolution or EGPRS).

A ray that is completely confined to the fiber core.

Hutchison 3G (Three), 3UK

A system in which signals may be sent in two directions, but not at the same time. In a half-duplex system, one end of the link must finish transmitting before the other end may begin.

Data transmission over a circuit capable of transmitting in either direction. Transmission can be bidirectional but not simultaneously.

One of the following elements: chlorine, fluorine, bromine, astatine, or iodine.

May be referred to as curly cord or curly handset lead.

An optical fiber with a hard plastic cladding surrounding a step index silica core.

The address is represented by six sections of two hexadecimal addresses; for example, 00-03-fe-e7-18-54. This number is hard-coded into networking hardware by manufacturers. Also called the physical address; see also MAC address.

Connects the transmission pins directly to the receiving pins, allowing diagnostic software to test whether a device can successfully transmit and receive.

High Density also known as HDC or HD

High Density also known as HDC or HD

(1) The central facility where signals are combined and distributed in a cable television system or a public telephone system. See central office.