Glossary

Denotes a coaxial cable type (similar to RG-8) that is commonly used with Ethernet (10Base-5) backbones. Originally, thicknet cabling was the only cabling type used with Ethernet, but it was replaced as backbone cabling by optical fiber cabling. Thicknet cable has an impedance of 50 ohms and is commonly about 0.4 inches in diameter.

Denotes a coaxial cable type (RG-58) that was commonly used with Ethernet (10Base-2) local area networks. This coaxial cable has an impedance of 50 ohms and is 0.2 inches in diameter. It is also called cheapernet due to the fact that it was cheaper to purchase and install than the bulkier (and larger) thicknet Ethernet cabling. The maximum distance for a thinnet segment is 180 meters.

The standards body that helped to author the ANSI/TIA/EIA-568-B Commercial Building Telecommunications Cabling Standard in conjunction with EIA and that continues to update it, along with standards for pathways, spaces, grounding, bonding, administration, field testing, and other aspects of the telecommunications industry. See Chapter 2 for more information.

A type of optical fiber cable construction where each glass fiber is buffered tightly by a protective thermoplastic coating to a diameter of 900 microns. High tensile strength rating is achieved, providing durability and ease of handling and connectorization.

An optical fiber with a buffer that matches the outside diameter of the optical fiber, forming a tight outer protective layer; typically 900 microns in diameter.

In an optical time-domain reflectometer, the circuit used to coordinate and regulate the testing process.

A type of electrical conductor composed of a number of tiny threads, each having a fine, flat ribbon of copper or other metal closely spiraled about it. Used for smallsized cables requiring limpness and extra-long flex life.

(1) A polarity designation of one wire of a pair indicating that the wire is that of the primary (common) color of a five-pair cable (which is not commonly used anymore) group (e.g., the white/blue wire of the blue pair). (2) A wiring contact to which the tip wire is connected. (3) The positive wiring polarity. See also ring.

A telephony term used to describe the conductor of a pair that is grounded at the central office when the line is idle. This term was originally coined from its position as the first (tip) conductor of a tip-ring-sleeve switchboard plug. See also tip.

Tower Mounted Amplifier – generically referred to as an MHA TMA-D: Duplexed Tower Mount Amplifier that combines Tx and Rx ports from the radio system and connects to a single antenna.
TMA-S: A receive only Tower Mount Amplifier is installed between the receiving antenna and the radio to boost weak signals.
TMA-DD: A dual duplex tower mount amplifier used for radio systems with a single transmission line connection for transmit and receive.

A threaded connector used to terminate coaxial cables. TNC is an acronym for Threaded Neill-Concelman (Neill and Concelman invented the connector).

A media access method in which a token (data packet) is passed around the ring in an orderly fashion from one device to the next. A station can transmit only when it has the token. The token continues around the network until the original sender receives the token again. If the host has more data to send, the process repeats. If not, the original sender modifies the token to indicate that the token is free for anyone else to use.

A ring topology for a local area network (LAN) in which a supervisory frame, or token, must be received by an attached terminal or workstation before that terminal or workstation can start transmitting. The workstation with the token then transmits and uses the entire bandwidth of whatever communications media the token ring network is using. The most common wiring scheme is called a star-wired ring. Only one data packet can be passed along the ring at a time. If the data packet goes around the ring without being claimed, it eventually makes its way back to the sender. The IEEE standard for Token Ring is 802.5.

A push-button telephone dial that makes a different sound (in fact, a combination of two tones) for each number pushed. The technically correct name for tone dial is dual-tone multifrequency (DTMF) since there are two tones generated for each button pressed.

A small electronic device used to test network cables for breaks and other problems that sends an electronic signal down one set of UTP wires. Used with a tone locator or probe.