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10/100 - 802.3 Ethernet reference; 10BaseT is 10 Mbps, 100Baast 10 is 100 Mbps, and 10BaseF is 100 Mpbs over fiber optic. As 10BaseT and 100BaseT can interconnect, this type of network is commonly called a Ten-One Hundered Network.

10BaseT - 802.3 ethernet 10Mbps LAN standard.

100Baset - 802.3 ethernet 100Mpbs LAN standard.

66 Block - Aka 66M1150 Termination Block, used on distribution frames and any other solid 22 to 24 wiring application to terminate twisted-pair wire.

911 - Emergency Service Telephone number; handled directly by an emergency dispatch service, resulting in a separate charge on telephone bills.

A

Access - (1) Point at which entry is gained into a circuit or a network interconnection; may be switched or dedicated. (2) Ability to obtain data from a storage device or peripheral. (3) Type of connection between customer premises equipment (CPE) and an interexchange carrier's network.

Access Charge (Carrier Common-Line Charge) - the charge made by local phone companies to long distance carriers to connection toe far-end portion of a call.

Access Line - Connection provided by a telephone company - which runs between the central office or collocation within the central office, and the customer's premises.

Access Link - Local phone line connecting customer to the central office switch, giving access to a long distance carrier - provides dial tone or private line communications capability.

Access Node - Reside in a central office, or part of a leased space agreement, and provided by local carrier loops which provide a connecting point for data transport or data-packet networks.

Access Point (AP) - Another name for a cross box where telephone cables are cross connected.

Access Service Request - Used by special service providers such as frame relay or long distance private line for getting wire facilities between their point of presence and the customer location - the request to the local telephone company to provide the line between them and the customer network interface.

Access Tandem - Switch in which all inter and outer area code traffic is handled - located in a telephone company central office or note; the main local exchange carrier in an area code where long-distance service handoff occurs.

Account Code - Used in a multi-line office to determine individual employee long distance use & charges.

Address Resolution Protocol (ARP) - A set of communications instructions/rules sued by communications interface equipment & computers to map or forward IP data packets to a hardware address.

Advertising (Router) - In order for routers to maintain accurate information about their network surroundings (assisting in accurate and efficient passing of data packets) - the process in which routers send routing tables updates, and/or service updates, at specific intervals.

Aerial Cable - Power, Telephone, and or Coax cable that is attached to power or telephone poles strung through the air.

Aggregate Bandwidth - Including payload and overhead - the total bandwidth of a broadband circuit and its tributaries. For example - a T-1 line has an average aggregate bandwidth of 1.544 Mbps.

Aggregation Device - Two B channels (64 Kbps) combined with an ISDN terminal adaptor for a single channel of 128 Kbps.

AIR (Allowed Information Rate) - Maximum data transfer rate, that a frame relay data link connection allows - which is equal to the combined total CIR (Committed Information Rate) and the EIR (Excess Information Rate) of the DLC (Data Link Connection)

Airline Mileage - The actual mileage between two cities that is used to determine long-distance private line pricing.

AMI (Alternate Mark Inversion) - Line format that inverts a the polarity of a digital signal into alternate 1s bits.

Analog - A signal having an infinite number of levels per cycle, whereas digital has only two levels per cycle (on or off).

Anonymous Call Rejection - Phone company feature that will not allow anonymous calls to be completed. Also available on some caller ID units that have anonymous call rejection built in.

Answer Supervision - The ability of a central office to detect when a long distance call has been answered - used to determine whether or not the call can be billed.

Application Layer - In the OSI communications model, the seventh and highest layer, which is the function of connecting an application file or program to a communications protocol.

Area Code - Three-digit numbering plan in North America which permits direct distance dialing.

Asymmetric - Communications transmissions that are full or half duplex, and one direction is fast, the other slow. Sometimes channels are referred to as "upstream" for slow, and "downstream" for fast.

Asymmetric Digital Subscriber Line (ADSL) - Also referred to as ADSL Full Rate or G.992.1. Physical layer protocol supporting up to 8 Mbps bandwidth downstream, and up to 1 Mbps upstream. Good for video on demand, internet browsing, and remote LAN access. Base range is 18,000 feet, extendable via ADSL repeaters up to 48,000 feet (or more using fiber optic)

Asynchronous - Where each communicating device works at its won speed without external timing (example - modems, FAX machines, TCP/IP communications are asynchronous)

ATM (Asynchronous Transfer Mode) - A high-speed switching technique that transmits voice, data, and video via fixed sized cells - kind of like envelopes that carry the same number of bits. Data is transmitted and received in 53 bytes or octets at a time - 48 customer bytes (payload) and 5 bytes for control and addressing. Cost is lower than many small circuits, and only one adapter is needed to connect everything.

Automatic Call Distributor (ACD) - PBX device that handles heavy incoming call volume. It send a call to the first available answering position or, if all positions are busy, plays a recorded message and puts calls in a queue until an answering position becomes available.

Automatic number identification (ANI) - The customer's billing number - aka Caller Identification Number or Caller ID.

Available Bit Rate (ABR) - Quality of Service (QOS) used for connections that are not delay or time sensitive - for example, connections that carry spontaneous or bursty data.

Automated Attendant (AA) - Used on voice mail systems; answering machine that asks callers to push 1 for sales, etc.; capable of routing callers to a dial by name directory.

B

B Channel - ISDN circuit "bearer" channel, which carries 64 kbps of end user data. The other channel is referred to as the data channel (D Channel) - 16 kpbs, carrying phone company signaling and other information needed to make the circuit work.

Backbone - The part of a network that connects smaller segments of a network together - they carry high concentrations of data traffic between on ramps and off ramps of networks.

Backhaul - Long distance service term, which means routing a call past its designation and then back. Can be used as a cost savings tool - by routing calls through cities with less expensive rates, then back to the original destination.

Backward Explicit Congestion Notification (BECN) - Within a data packet, an overhead bit traveling in a frame-relay network. Bit is set to one if the packet travels through an area of network congestion that is opposite of its flow, signaling to higher level protocols to take flow control action.

Band - Range of frequencies between two defined limits.

Bandwidth - The measure of capacity of a communications channel. Digital channels measure this in bits per second, while analog telephone lines measure this capacity in hertz (the difference between the highest and lowest frequency in the channel)

Bandwidth Allocation - Dynamic assignment of communication resources to users and software programs within a network, using predetermined priority levels for data based on time sensitivity.

Bandwidth Control Elements (BCE) - Parameters of a frame-relay data link connection, determining not only the amount of data that will be accepted by the network over time, but also the priority of that data.

Basic Rate Interface (BRI) - On an ISDN line, the smaller line which consists of two "B" channels (64 kbps each). With the appropriate phone company service package and correct terminal adapter, it is possible to talk on one B channel while transmitting data on the second B channel.

Baud Rate - Actual bit rate on a communications line.

Bay - Where peripheral devices in a computer, such as a disk drive, are stored.

Bc (Committed Burst) - Amount of data permitted, over a specific time frame, onto and over a frame-relay network DLC.

Bell Operating Company (BOC) - One of the 22 local Bell telephone companies owned by AT&T before 1984.

Billed Telephone Number - Number regarded as the billing account number on a phone bill; if there are multiple numbers on one account, using the billed telephone number allows billing for multiple numbers without generating multiple bills.

Binary - Number system that counts with a 0 and 1. Example: 1 = 0001, 2 = 0010, 3 = 0011, 4 = 0100.

Binary 8-zero Substitution (B8ZS) - Transmission format used to prevent too many consecutive zeros from being transmitted - if a sequence of 8 bits are detected prior to being transmitted, they are replaced with a different pre-determined byte that is not all zeros.

Binary Coded Decimal (BCD) - Four bit code representing the numbers zero through nine in binary. Shortcut for entering many binary numbers into a machine language program.

BIOS - Basic Input Output System. On a personal computer (PC), it contains dynamic RAM registers used as buffers for sending bits to specific intended hardware.

Bit (Binary Digit) - A unit of data represented either as a 1 or 0. Most data devices, a bit is physically a positive 5 volts or 0 volts.

Bit Error Rate (BER) - The ratio of bad bits to good bits - a way to measure data integrity.

Bit Parity - By adding up the value of bits in a bit stream, the total would be either even or odd - if the total value is even, a 1 is added to the end of the stream, and a 0 if the total value is odd. if the value at the beginning of a bit stream does not equal to the value when the stream is received, a request to retransmit is made. Bit Parity then, is a way to confirm that transmitted data is not corrupt or distorted during the transmission.

Bit Rate - Average number of bits transmitted per second over a communications line, including encoding, compression, and retransmission of corrupted data.

Bits per Second (BPS) - Average net number of transmitted bits over a communications line, over a time period of one second, including encoding, compression, and retransmission of corrupted data.

Blocking - Results in a fast busy signal; happens when the central office or PBX blocks the line once it has fully utilized its capacity to connect calls.

Bonding - IDSN term, describing the joining of two 64 Kbps channels into one 128 Kbps channel.

Border Gateway Protocol (BGP) - Interdomain routing protocol; exchanges reachability information with other same system-type routers in an Internet core router applications.

Border Gateway Protocol version 4 (BGP4) - Reduces the size of routing tables by aggregating routes listed in a router's memory; the predominant interdomain protocol used on the Internet.

Bps (bits per second) - The number of bits send in one second.

Bridge - a device that connects local or remote networks together; used for small numbers of networks. If you want to connect more than four or five networks, you would use a router instead.

Broadband - Where multiple transmissions share a communications path.

Broadband Integrated Services Digital Network (BISDN) - Telecommunications service concept. Widespread use of Internet protocols, xDSL in local networks, and ATM feature flexibility are enablers of BISDN; ATM and Internet use have evolved into BISDN. Concept features the ability to provide "on demand" bandwidth for various services, such as video & data transfer.

Byte - Equals eight bits. Also called an Octet.