Term
Definition
ABR
Available Bit Rate.
ACR
Attenuation Crosstalk Ratio. The difference between attenuation and crosstalk, measured in dB, at a given frequency. Important characteristic in networking transmission to assure that signal sent down a twisted pair is stronger at the receiving end of the cable than are any interference signals imposed on that same pair by crosstalk from other pairs.
ADSL
Asymmetric Digital Subscriber Line
Attenuation
The decrease in magnitude of a signal as it travels through any transmitting medium, such as a cable or circuitry. Attenuation is usually expressed logarithmically as the ratio of the original and decreased signal amplitudes. It is usually expressed in decibels (dB).
Backbone
The cable used to connect all systems of a multi-level distributed system to an intermediate system.
Backshell
Housing on a connector that covers the area where the cable conductors connect to the connector contacts. It can be a metal housing providing continuity of the shield through IDC connectors.
Balanced Line
A cable having two identical conductors which carry voltages opposite in polarity, but equal in magnitude with respect to ground, suitable for differential signal transmission.
Balun
Balanced to unbalanced (Bal-un) transformer used to connect an unbalanced transmission line (i.e. coaxial cable) to a balanced system or cable, or vice versa. It can also provide impedance transformation, as 300 ohm balanced to 75 ohm unbalanced.
Baud
Rate of digital transmission equal to the reciprocal of the time of one output signaling element.
Beldfoil
Belden trademark for highly effective electrostatic shield of reinforced metallic foil.
Bend Radius
Radius of curvature that a flat, round, fiber optic or metallic cable can bend without any adverse effects.
Bit
One binary digit.
Bit Error Rate
The number of errors occurring in a system per unit of time (e.g. bits per second)
Bits Per Second
The number of binary bits that can be transmitted per second (bps) - i.e. Mbps (Mega = million), Gbps (Giga = billion).
BPS
Bits per second (see).
BPSK
Binary Phase Sift Keying. A type of digital transmission where two phases of the signal are possible to represent binary one and zero.
Braid
A group of textile or metallic filaments interwoven to form a tubular flexible structure which may be applied over one or more wires, or flattened to form a strap.
Braid Angle
The angle between a strand of wire in a braid shield and the longitudinal axis (i.e.axis along the length of the center) of the cable it is wound around.
Breakout
The point at which a conductor or conductors are separated from a multi-conductor cable to complete circuits at various points along the main cable.
BRI
Basic Rate Interface ISDN.
Broadband
The technique used to multiplex multiple networks on a single cable without interfering with each other. Technologies that allow you to transmit or receive higher volumes of data at higher speeds.
Byte
A group of eight adjacent binary digits (8 bits).
Cable Modem
A device that enables you to hook up your PC to a local cable TV line and receive data at much faster rates than telephone modems and ISDN lines. A strong competitor to DSL telephone service.
Capacitive Crosstalk
Cable crosstalk or interference resulting from the coupling of the electrostatic field of one conductor upon one or more others.
Category
Rating of a local area network (LAN) cable established by TIA/EIA to indicate the level of electrical performance.
Category Cables
Belden manufactures Category 3 to 7 cables, all high performance twisted pair data cables. The higher the category number, the greater the bandwidth. Category 7 is currently the highest performance telecommunication wire available. Ours is certified to applicable UL standards.
CBR
Constant Bit Rate.
Channel
The horizontal cable including the workstation outlet and patch panel in the telecommunications closet plus a maximum combined length of up to ten meters of patch cable at each end (maximum length of 100 meters).
Characteristic Impedance
In a transmission cable of infinite length, the ratio of the applied voltage to the resultant current at the point the voltage is applied. Or the impedance which makes a transmission cable seem infinitely long, when connected across the cable's output terminals.
COLS
Commercial Online Service.
CPU
Central Processing Unit.
Crosstalk
A type of interference caused by signals from one pair or cable being coupled into adjacent pairs or cables. Can occur with audio, data, or RF signals.
CSMA/D
Carrier Sense Multiple Access/Collision Detection.
DES
Data Encryption Standard.
DHCP
Dynamic Host Configuration Protocol.
Digital Signal
An electrical signal which possesses two distinct states (on/off, positive/negative).
Disturbed Conductor
A conductor that receives energy generated by the field of another conductor or an external source. e.g. the quiet line.
DOCSIS
Data Over Cable Service Interface Specification (trade mark). Defines interface requirements for cable modems involved in high-speed data distribution over cable television system networks.
Drop Cable
In a CATV system, the transmission cable from the distribution cable to a dwelling.
DSL
Digital Subscriber Line. A technology for bringing high-bandwidth information to homes and small businesses over ordinary copper telephone lines. A DSL line can carry both data and voice signals, with the data part of the line remaining continuously connected. Currently competes with the cable modem in bringing broadband services to homes and small businesses.
ELFEXT
Equal Level Far End Crosstalk (dB). A subtraction of attenuation from FEXT. By subtracting the attenuation, ELFEXT negates the effects of attenuation on the interference as it propagates down the cable, thus bringing it to an "equal level".
FEC
Forward Error Correction.
FEXT
Far End Crosstalk. Crosstalk induced on the pairs, measured at the "far" end of the cable, referenced to the near end input signal. Usually expressed in decibels.
HDSL
High bit-rate Digital Subscriber Line.
Headroom
The amount by which a cable ACR exceeds the specified requirements. The TIA/EIA 568B standard specifies a minimum of 10 dB of ACR for Category 5e certification at 100 MHz.
Horizontal Cable
Cable used between the workstation outlet and the telecommunications closet. Limited to 90 meters maximum per TIA/EIA 568B.1.
HSCDS
High-Speed Cable Data Service.
HTML
Hypertext Markup Language.
HTTP
Hypertext Transfer Protocol.
I/O Interconnection
Input/Output interface to the "outside world."
IDSL
ISDN Digital Subscriber Line.
IETF
Internet Engineering Task Force.
IGMP
Internet Group Management Protocol.
Inductive Crosstalk
Crosstalk resulting from the coupling of the electromagnetic field of one conductor upon another.
INMS
Integrated Network Management System.
Insertion Loss
A measure of the attenuation of a cable and/or component(s) by determining the output of a system before and after the device is inserted into the system.
IP
Internet Protocol.
IPCDN
IP Over Cable Data Network working group of the IETF.
IRC
Inter Relay Chat.
ISDN
Integrated Services Digital Network. An alternative to telephone modems that allows digital transmission over ordinary telephone copper wire and other media. Home and business users can get highly graphic Web pages more quickly through ISDN adapters than through dial-up connections.
ISP
Internet Service Provider.
Jacket
Pertaining to wire and cable, the outer protective covering that may also provide additional insulation.
LAN
Local Area Network. A data network connecting any number of users, intended to serve a small area. A group of computers and associated devices that share a common communications line and typically share the resources of a single processor or server within a small geographic area.
LEC
Local Exchange Carrier.
Permanent Link
The horizontal cable including the workstation outlet and patch panel in the telecommunications closet plus two meters of cable at each end for testing. Limited to a maximum of 90 meters in TIA/EIA 568B.1.
Loaded Line
A transmission line that has lumped elements (inductance or capacitance) added at uniformly spaced intervals. Loading is used to provide a given set of characteristics to a transmission line.
Loading
A transmission line that has lumped elements (inductance or capacitance) added at uniformly spaced intervals. Loading is used to provide a given set of characteristics to a transmission line.
Local Area Network
A data network connecting any number of users, intended to serve a small area. See also LAN.
MAC
Media Access Control (layer of OSI Reference Model).
MAN
Metropolitan Area Network. A data network intended to serve the area of a city or an area of similar size.
MB
Megabyte.
Mbps
Mega bits per second - the number of bits, in millions, transmitted per second.
Metropolitan Area Network
A data network intended to serve the area of a city or an area of similar size. See also MAN.
Modem
Modulator-Demodulator. Device that converts signals in one form to another form compatible with another kind of equipment.
MTP
Simple Mail Transfer Protocol.
Mutual Capacitance
Effective capacitance between two conductors when the effects of the other conductors and shield, if present, are removed.
NAP
Network Access Point.
Network
A network is a method of data communications between computers.
NEXT
Near-end Crosstalk. Crosstalk induced on the pairs, measured at the end "near" the transmitter. Usually expressed in decibels.
Nibble
One half byte (4 bits).
NOC
Network Operations Center.
Non-Paired Cable
Cable with two or more cabled conductors that are not in a paired configuration.
OSI
Open System Interconnect (Model for networking protocols).
OSS
Operations Support Systems.
Paired Cable
Cable with conductors cabled in groups of two.
Parallel Digital
Digital information that is transmitted in parallel form. The digits are sent on separate conductors rather than sequentially on one transmission line (serial). Often used informally to refer to parallel digital television signals.
Patchcord
A flexible piece of cable terminated at both ends with plugs. Used for interconnecting circuits on a patchboard, in a wiring closet, or at the work area.
PC
Personal Computer.
PHY
Physical (layer of OSI Reference Model). See also Physical Layer.
Physical Layer
The actual portion of a network that is used to physically connect computers of a network and over which the data is transmitted - the cable.
PPP
Point-to-Point Protocol.
Premise Cabling
Refers to the entire cabling system used for voice, data, video and power on a user's premise. For Local Area Networks, the cabling of choice includes unshielded twisted pairs (UTP), fiber optic and coaxial cables. Of these, the UTP market is the largest, with greatest demand for cables with four pairs that meet certain standards of performance, such as Category 5 and Category 5e.
PRI
Primary Rate Interface ISDN.
Propagation Delay
Time required for a signal to pass from the input to the output of a device.
Pseudo Random NRZ
A wave form of binary signals that may be used in a computer system. It is called NRZ, Non-Return to Zero, because the voltage does not return to zero after each bit.
RDC
Regional Data Center.
Reflection
The change in direction (or return) of waves striking a surface. For example, electromagnetic energy reflections can occur at an impedance mismatch in a transmission line, causing standing waves.
Reflection Loss
The part of a signal which is lost due to reflection of power at a line discontinuity.
RJ-45
Modular telecommunications connector.
RSVP
Resource Reservation Protocol.
RTP
Real-Time Transport Protocol.
S-CDMA
Synchronous Code Division Multiple Access.
S-HDSL
Single-pair High bit-rate Digital Subscriber Line.
ScTP
Screened Twisted Pair. Premise network cable with an overall foil shield.
SDSL
Symmetric Digital Subscriber Line.
Serial Digital
Digital information that is transmitted in serial form. SDI informally refers to serial digital television signals that conform to the SMPTE 259M standard. See also Serial Digital Interface.
SNMP
Simple Network Management Protocol.
Standing Wave
The stationary pattern of waves produced by two waves of the same frequency traveling in opposite directions on the same transmission line. The existence of voltage and current maxima and minima along a transmission line is a result of reflected energy from an impedance mismatch.
Standing Wave Ratio (SWR)
A ratio of the maximum amplitude to the minimum amplitude of a standing wave stated in current or voltage amplitudes. See also Standing Wave.
STP
Shielded Twisted Pair(s).
Structural Return Loss
Magnitude of the internal cable reflections, measured in decibels, relative to the actual cable impedance, not the system impedance. Measure of signal reflections caused by the structure of the cable without the additional reflections from any impedance mismatch between the cable and the measuring equipment. Measure of internal cable reflections using a reference impedance in the measuring equipment that is adjusted to the nominal or average impedance of the cable. See also Return Loss
Sweep Test
Testing a characteristic of a cable or device across a range of frequencies. In cable, it usually implies return loss or structural return loss (see also).
TCP/IP
Transmission Control Protocol/Internet Protocol.
TIA-EIA 568B
"Commercial Building Telecommunications Wiring Standard" defines a generic telecommunications wiring system for commercial buildings that will support a multi-product, multi-vendor environment. It also provides direction for the design of telecommunications products for commercial enterprises.
TP-PMD
Twisted Pair-Physical Medium Dependent.
Transmission Line
An arrangement of two or more conductors, a coaxial cable, or a waveguide used to transfer signal energy from one location to another.
Transmission Line Cable
Two or more conductors placed within a dielectric material in such a way as to control the electrical characteristics.
Twinax Cable
Cable with two twisted conductors with established electrical properties (one pair=twinax).
Twisted Pair
Two lengths of insulated conductors twisted together. The traditional method for connecting home and many business computers to the telephone company. Gets its name because two insulated copper wires are twisted together, both of which are needed for each connection. In commercial environments, performance of data transmission can be improved by adding a composite tape to the wire. This is known as shielded twisted pair.
Two pair premise wiring
Refers to the two pairs of voice grade (low bandwidth) twisted pair wire installed in most homes since the 1950s. The extra pair makes it possible for you to add another line when you need it.
Unbalanced Line
A transmission line in which voltages on the two conductors are unequal with respect to ground. A coaxial cable is a common type of unbalanced line.
UTP
Unshielded Twisted Pair(s).
VC/MTM
Variable Constellation/Multi-Tone Modulation.
VDSL
Very high bit rate Digital Subscriber Line.
Velocity of Propagation (VP)
The transmission speed of electrical energy in a length of cable compared to speed of light in free space. Usually expressed as a percentage.
WAN
Wide Area Network.