Glossary

802.11 An industry set of standards for wireless local area network (WLAN) communications.
AC Power Alternating current. This is usually 120 V and is delivered by the local power utility.
ADSL Asymmetrical Digital Subscriber Line - Bellcore's term for one-way T-1 to the home over the plain old, single twisted pair wiring already going to homes.  ADSL is designed to carry one-way video to the home with control signals returning from the home at 16Kpbs.
Ah Amp hour. A system that tells you how many hours a battery will last based on the amperage demanded. A 100 amp-hours rating means that a battery will supply 100 Amps for one hour; 50 amps for two hours or 10amps for ten hours.
ALEC A carrier providing local access & transport other than the primary LEC. Synonymous with ALTERNATIVE ACCESS PROVIDER.
Amp Ampere. The unit of measurement of electric current.
Analog The signal being transmitted - voice, data, video - is "analogous," to the original signal. "Analogous," means "similar to." Telephone transmission and/or switching which is not digital.
Asset Recovery Investment recovery. The recouping of investment from assets by reusing or reselling. 
ATM (Asynchronous Transfer Mode) A network technology for both LANs and WANs that supports real-time data, voice and video. Very high speed telecom, transmission, high bandwidth, low-delay, packet like switching and multiplexing.
Backbone The top level or main lines of a communication network that handles the major traffic. LANS are connected to the backbone via bridges and/or routers.
Bandwidth Refers to the transmission capacity of information that can be transmitted through a connection in a fixed amount of time. Usually measured in bits per second (BPS).
Battery An electrochemical cell that converts stored chemical energy into electrical energy.  There are two types of batteries: primary batteries (disposable batteries) and secondary batteries (rechargeable batteries).  
Bridge A device used to connect networks, using similar or dissimilar media and signaling systems such as Ethernet, TokenRing.  Also called data link relay.
Broadband High-speed transmission frequencies used to transmit voice, data, or video signals simultaneously, typically on coaxial cable.
Cabinet An enclosed housing for terminating telecommunications cables, wiring and connection devices.    
Cable Management Cable management means to neatly secure electrical, data, and other cables by using cable trays, ladders, and baskets to support cable throughout the premises.
CAT 5 Cat5, Cat-5, or Category 5 cable is a current industry standard for network and telephone wiring. Sometimes called Ethernet Cable, CAT 5 cabling is used in computer networks such as Ethernet and ATM, and also to carry other signals such as telephony and video. Data rate of 100 Mbps.
CAT3 Category 3 - unshielded twisted pair wire that supports a data rate of 10Mbps
Channel Bank A multiplexor device that merges low-speed voice or data lines into one high-speed digital line and vice versa.
Circuit Breaker A protective electrical device that is used to monitor and control the amount of amps being sent through wiring.
Clear Channel A digital circuit where no framing or control bits (i.e., for signaling) are required, thus making the full bandwidth available for communications.
CLEC Competitive Local Exchange Carrier 
CO Central Office - Telephone company facility where subscribers' lines are joined to switching equipment for connecting other subscribers to each other, locally & long distance.
Connector A plug and socket device that connects wires or fibers in cable to equipment, or other wires or fibers.  
Converter A device used to convert from one set of codes, or transmission media to another.
CPE (Customer Provided Equipment) or (Customer Premises Equipment) Terminal communications equipment that is on the customer's premises.
Crimp Tools A tool used to attach or form connectors onto cables.
Cross-connect Distribution system equipment used to terminate and administer communications circuits.  In a wire cross connect jumper wires or patch cords are used to make circuit connections.  In an optical cross connect, fiber patch cords are used.  The cross connect is located in an equipment room, riser closet, or satellite closet.
CSU (Channel Service Unit)  A device that terminates the external line at the customer's premises. The CSU receives and transmits signals to and from a WAN line and provides a barrier for electrical interference from either side of the unit.
DACS (Digital access and cross-connect system-DACS, DCS or DCCS) is a digital switching device used for routing T1 lines. The DACS can cross-connect a T1 line in the system with any other T1 line in the system.            
DC Power Direct Current. The current is on one direction.
DCS (Digital Cross Connect System) A digital switching system that interconnects channels between digital multiplexed lines (usually t-carrier lines).
DDS Digital Data System. A private line digital service, typically with data rates at 2400; 4800; 9600 and 56,000 bits per second.  It is offered on an inter-LATA basis by AT&T and on an intra-LATA basis by the Bell operating companies.
Distribution The portion of a switching system in which a number of inputs is given access to an equal number of outputs.                              
DS-0 Digital Service, level 0. It is 64k the worldwide standard speed for digitizing one voice conversation using pulse code modulation (PCM).  There are 24DS-0 channels in a DS-1.
DS-1 Digital Service, level 1. It is 1.544 Mbps in North America, 2.048 Mbps elsewhere.  Standard 1.544 Mbps is 24 voice conversations each encoded at 64k.  Standard for 2.048 Mbps is 30 conversations.
DS-3 Digital Service, level 3. Equivalent of 28 T1 channels, and operating at 44.736 Mbps. Also called a T3.
DS-4 Digital Service, level 4.  274,176,000 Mbps.  168T1s. 168DS-1s. 4032 standard voice channels.
DSL (Digital Subscriber Line) A family of digital lines provided by CLECs that provides digital data transmission over the standard copper telephone lines of a local telephone network.
DSLAM Digital Subscriber Loop Access Multiplexer
DSU (Digital Service Unit, also called Data Service Unit) Converts RS-232-C or other terminal interface to DSX-1 interface. It is used in digital transmission that interfaces between data terminal equipment (DTE) and a transmission facility such as T1 or E1.          
DSX (Digital Cross Connect) This is a standard that defines the voltage, pulse width and plug and socket for connecting DS-1 (T1) signals.
DSX-1 Digital Signal Cross-Connect Level 1. The set of parameters for cross-connecting DS-1 lines.
DSX-3 Digital Signal Cross-Connect Level 3. The set of parameters for cross-connecting DS-3 lines.  The designation for the DS-3 point of interface (cross connect).
E1 The European equivalent of the North American 1.544 Mbps T1, except that E1 carries information at the rate of 2.048 Mbps.  This is the rate used to transmit 30 64k digital channels for voice or data calls, plus a 64k channel for signaling, and a 64k channel for framing.
ESF Extended Super Frame or Extended Super frame Format.  A T1 format that used the framing bit for non-intrusive signaling and control.
Ethernet Ethernet is a standard communications networking technology for local area networks.
FDDI Fiber Distributed Data Interface.  100 million bits per second fiber optic LAN.  It is an ANSI standard. It uses a "counter rotating" token ring topology.
Fiber Cable A generic term used for both plastic and glass fiber optic cables used for high-speed communications.  
Fiber Channel An industry standard for transmitting signals at 100 Mbits/s to 4.25 Gbit/s over a fiber line or at slower speeds for copper lines.
Fiber Optics A technology that sends pulses of light through glass or plastic optical fiber to transmit information.
Frame Relay A high-speed protocol standard designed to provide more efficient ways of transmitting infrequent data traffic between one device to another or between LAN and end-points in a WAN.
GR303 A set of technical specifications that help define the next generation of digital loop carrier (DLC) interconnection.
HDSL High Data Rate DSL. Delivers symmetric service at speeds up to 2.3 Mbps in both directions.  It uses 1, 2, or 3 twisted copper pairs.  Does not provide standard telephone service at the same time.
HDSL2 Second Generation HDSL.
HSSI High Speed Synchronous Interface.  A serial data communication interface optimized for high speeds up to 52 Mbps.  Used for connecting an ATM switch to a T-3 DSU/CSU.
Hub A device to which all clients and servers are wired in an Ethernet network.
IAD (Integrated Access Device) A device that multiplexes voice, data or video technologies in the customer's premises onto a single telephone line for transmission to the carrier.  It also demultiplexes the incoming streams into their respective channels.
IMUX Inverse Multiplexer.  A device that provides the function of a higher speed service by providing synchronization and transport across several lower speed services.  Inverse multiplexing may be accomplished with both switched and dedicated services.
Integration The combining of different services (such as voice, data, and video) onto a common communication system.
Inverter A device which converts direct current electricity to alternating current electricity.          
IP Internet Protocol.  Part of the TCP/IP family of protocols describing software that tracks the internet address or nodes, routes outgoing messages, and recognizes incoming messages.
ISDN (Integrated Services Digital Network) An international standard for switched, digital dial-up telephone service for voice and data.
ISDN BRI Basic Rate Interface.  BRI which is 144,000 bps, 2B+D - Two bearer channels and one D channel to your desktop.  A wonderful service for your home or office because it can give you video conferencing and ultra fast data communications.
ISDN PRI Primary Rate Interface. The ISDN equivalent of a T1 circuit.  The Primary Rate Interface (delivered to customer premises) provides 23 B+D (North America) 1.544 Mbps.  It is a standard T1 line in the US and operates on two pairs, typically delivered on fiber.  30B+D (Europe) it is 2.048 Mbps, it is a standard T1 line in Europe which also operates on two pairs.  Designed for telephone switches, computer telephone and voice processing systems.
ISP (Internet Service Provider) A company  that provides access to the Internet to the user by dial-up, ISDN, cable, DSL, T1/T3 lines or fiber.
IXC Interexchange Carrier.  A carrier that provides inter-LATA (long distance) service.
Kbps The speed of data transmission stated as thousands of data bits per second.
LAN (Local Area Network)   A communications network that serves users within a confined geographical proximity.
LEC Local Exchange Carrier.  A carrier that provides services within a LATA and does not (generally) provide long distance services.  The LECS are often called "RBOCs" (Regional Bell Operating Companies), but LEC is a more exact term as there are many LECs that are independent companies.
M13 It joins DS-1 channels to a DS-3, It will take 28DS-1 inputs and combines them into single 45 Mbps stream.
Mbps The speed of data transmission stated as Millions of data bits per second.  
Media Conversion Converting from one transmission media to another.
Microwave A radio signal in the 1 to 40 GHz or from 1 to 300 GHz frequency range.
Modem (Modulate/demodulate) a modem modulates outgoing digital signals from a computer or other digital device to analog signals for a conventional copper twisted pair telephone line and demodulates the incoming analog signal and coverts it to a digital signal for the digital device.
Multiplexer Electronic equipment which allows two or more signals to pass over one communications circuit.       
Narrowband Up to and including T-1 or 1.544 megabits per second.
Network A telecommunications network that transmits any combination of voice, video and/or data between users. 
Network Management Monitoring an active communications network in order to diagnose problems and gather statistics for administration and fine tuning.
OC-1 Optical Carrier, level 1. The optical counter part of STS-1 (the basic rate, 51.840 Mbps, on which SONET is based). Direct electrical-to-optical mapping of the STS-1 signal with frame synchronous scrambling.  All higher levels are direct multiples of OC-1 (i.e., OC-3 = 3 times OC-1, etc.).
OC-12 SONET channel of 622.08 Mbps.
OC-48 SONET channel of 2.4 Gbps. Theoretically, SONET can go as high as 13 Gbps.
OC-N The optical interface designed to work with the STS-n signaling rate in a Synchronous Optical Network (SONET). Optical Carrier level N.  The optical signal that results from an optical conversion of an STS-N signal. N=1, 3, 9, 12, 14, 36.
OSS Operations Support System.  Methods and procedures which directly support the daily operation of the telecommunications infrastructure.
Patch Cable An electrical or optical cable, of  specific length, that is terminated at each end with a plug or socket used to connect one electronic or optical device to another for signal routing.
Patch Panel A panel, typically rack mounted, that houses cable connections or groups of sockets used to manually connect incoming and outgoing lines together in communications and electronic systems.
Pedestal A small green box that sits outside and houses cables coming in, cables going out and cable splices inside the box to join cables.     
Point to multi-point A communications network that provides a path from one location to multiple locations.
Point to point A communications line that provides a path from one location to another (point A to point B).
POTS Plain Old Telephone Service. Basic service supplying standard single line telephone, telephone lines and access to the public switched network.  All POTS lines work on loop start signaling (Loop start is the signal that typically takes your phone off hook to signal the phone system that you want to make a call.)
Power Equipment Devices that change one type of power to another.
Power Cable An assembly of two or more electrical conductors used for transmission of electrical power. They may be permanent wiring within buildings, buried in the ground, run overhead, or exposed.            
Protocol A procedure for adding order to the exchange of data.  A protocol is a specific set of rules, procedures or conventions relating to format and timing of data transmission between two devices.   A standard procedure that two data devices must accept and use to be able to understand each other.
Rack  A frame or cabinet into which hardware components are mounted.
Rack and Stack A term commonly to refer to the assembly of computer hardware within a system, computer rack or computer cabinet.         
Receiver Any device which receives a transmission signal.       
Rectifier An electrical device used to convert AC into DC current.
Router A system level function that directs a call to an application.  A router can find the best route between any two networks.
SCADA (Supervisory Control And Data Acquisition) A process control application used extensively by utility companies to monitor and manage distribution facilities.
SDSL Synchronous digital Subscriber Loop.  Speeds up to 1Mbps are possible in both directions up to about 10,000 feet
Serial Serial is a telecom term that refers to "one after another." Data transmissions that are serial are ones that come in streams of data - one after another - one bit following the previous bit.     
Signal An electronic wave or light pulse used to convey information over wire, fiber or wireless application.  
SONET (Synchronous Optical NETwork) An international set of standards for the transmission of digital information over optical interfaces.  The "synchronous" designation refers to the characteristic that portions of the data stream may be cross-connected to other portions without demultiplexing.  That is, all component portions of the SONET signal may be tied to a single reference clock. A fiber-optic transmission system for high-speed digital traffic which is a standard for connecting fiber-optic transmission systems.
STS-n A fundamental unit of 51.840 Mbps in the SONET hierarchy, with "n" representing the integral multiples.  The most common values of "n" are 1, 3, 6, & 12.  "STS" indicates that this is an electrical rather that optical signal.
Switch A mechanical or electronic device that directs the flow of electrical or optical signals from one destination to another.
T1 1.544 Mbps point-to-point, dedicated, digital circuit, U.S. carriers use to transmit digital channels for voice or data calls, plus additional Kbps for signaling and framing. If SE or ESF framing is used, the information-carrying (bearer) portion of the signal is 1.536 Mbps.  In common usage, "T1" has come to refer to the transmission speed, the circuits, and the services.
T3 44.736 Mbps point-to-point, digital dedicated line, that U.S. carriers use to transmit digital channels for voice or data calls.   28 T1 lines or 45 Mbps. Capable of handling 672 voice conversations
TDM (Time Division Multiplex) A standard for transmitting several of separate data, voice and/or video signals simultaneously over one communications medium by interleaving a piece of each signal one after another.
Telephony Meaning "sound over distance" or to electronically transmit the human voice.
Transmission Sending electrical signals carrying information over a line to a destination
Transmitter An electronic device which, usually with the aid of an antenna, generates an electromagnetic signal such as radio, television, or other telecommunications.
UPS (Uninterruptible Power Supply) A device that keeps power going to a phone system when the power from the power company shuts down or is interrupted.  Usually includes an inverter, drawing its power from batteries, which generates an extremely "well-behaved" AC power.
VoATM Voice over ATM
VoDSL Voice over DSL line
VoFR Voice over Frame Relay
VoIP (Voice over IP) Any technology offering voice telephony services over the internet.     
WAN (Wide area network) A communication network that uses: telephone lines, satellite dishes, radio waves to cover long-distance communications over a larger geographic area than can be covered by a local area network.
Wireless Transmissions through the air or without wires.
xDSL A technology that exploits unused frequencies on copper telephone lines to transmit traffic typically at multi-megabit speeds.  Voice & high speed data can be sent simultaneously over the same line.
WSP Service Provider) A carrier authorized to provide wireless communications exchange services (examples: cellular carriers and paging service carriers)
Voice Compression Refers to the process of electronically modifying a 64Kbps PCm voice channel to obtain a channel of 32 kbps or less for the purpose of increased efficiency in transmission.