G - A UL portable power cable type with thermoset insulation and thermoset fiber reinforced oil-resistant jacket. Two to five #8 AWG or larger conductors with ground wires. Rated 2,000 V, 60°C maximum operating temperature when exposed to oil, 90°C maximum dry.
G-GC - A UL cable type. A portable power cable similar to Type G, but also having a ground check (GC) conductor to monitor the continuity of the grounding circuit.
Gain - The increase in signaling power caused by an amplifier and measured in decibels (dB).
Galvanized steel wire - Steel wire coated with zinc.
Gang strip - Stripping all or several conductors simultaneously.
Gas discharge tube - 1. A calibrated spark gap in a gas-filled chamber. These devices are relatively slow, activating in microseconds, but can handle very large surges. They work by shunting the surge or spike impulse around the protected circuit. 2. A method of protecting phone lines and phone equipment from high voltage caused by lightning strikes.
Gas filled cable - A self-contained pressurized cable in which the pressure medium is an inert gas having access to the insulation.
Gateway - Provides a convenient way to create a local network. It works as a combined router, switch and a NAT (network address translator) and is available from various manufacturers.
Gauge - A term used to denote the physical size of a wire. See AWG.
Gauss - A unit of magnetic induction (flux density) equal to 1 Maxwell lper cm2 or 10-4 weber per meter2.
General purpose instrumentation bus (GPIB) - A protocol standard defined by the IEEE. Often used on automated test and measurement equipment in manufacturing environments.
Gen-lock - A method used to synchronize one or more cameras by external means such as composite video, composite sync, horizontal or vertical sync.
GFCI - Ground fault circuit interrupter. A protective device that detects abnormal current flowing to ground and then interrupts the circuit. Required by the NEC for some installations.
GFI (ground fault interrupter) - A protective device that detects abnormal current flowing to ground and then interrupts the circuit.
Ghost - A shadowy or weak image in the received picture, offset either to the right or to the left of the primary image. It is the result of transmission conditions where secondary signals are created and received earlier or later than the primary signal.
GHz (gigahertz) - 1,000,000,000 cycles per second.
GIGA - A numerical prefix denoting one billion (109).
GLAND - A device used to terminate, seal and/or ground the metallic armor of a cable as it enters a metal enclosure. Sometimes called a fitting or a connector.
GND - Common abbreviation for ground.
GPRS (general packet radio service) - Wireless (cellular) telephony.
Graded index fiber - An optical fiber with a refractive index that gets progressively lower away from the axis. This causes the light rays to be continually refused by refraction in the core. It bends the rays inward and allows them to travel faster in the lower index of refraction region. This type of fiber provides high bandwidth capabilities.
Green goop - A viscous liquid that occasionally oozes from the end of installed PVC cables after many years in service. Generally found to be plasticizer (a component of PVC) contaminated with a copper compound that is green in color.
Ground - A voltage reference point that is the same as earth or chassis ground.
Ground check conductor (GC) - An insulated conductor commonly used in mining cables to monitor the health of the grounding conductor(s) in the cable.
Ground conductor - A conductor in a transmission cable or line that is grounded.
Ground fault - See FAULT GROUND.
Ground loop - Caused by different earth potentials in a system. Affects video pictures in the form of a black shadow bar across the screen or as a tearing in the top corner of a picture.
Ground plane - Expanded copper mesh that is laminated into some flat cable constructions as a shield.
Ground potential - Zero potential with respect to the ground or earth.
Grounded neutral - The neutral wire that is metallically connected to ground.
GTO - Gas tube sign cable, UL Listed as single conductor Type GTO-5 (5,000 V), GTO-10 (10,000 V) or GTO-15 (15,000 V), in sizes 18-10 AWG copper. This cable is intended for use with gas tube systems for signs, outline lighting, and interior lighting.
Guard band - 1. The unused bandwidth separating channels to prevent crosswalk in an FDM system. 2. In a broadband system, the frequency spectrum between the inbound and outbound pass bands.
GSM (global system for mobile communications) - A type of wireless (cellular) telephony.
GUI (graphical user interface) - Computer “human interface” that is based on icons rather than text. Pioneered by Xerox, implemented first by Apple, then by Microsoft Windows, Hewlett Packard and Unix-X-Windows.
Guy - A tension wire connected to a tall structure and another fixed object to add strength to the structure.