B3ZS: Bipolar 3 Zero Substitution
Bipolar 3 Zero Substitution (B3ZS) is a T-carrier line code in which bipolar violations are deliberately inserted if the stream of user data contains a string of 3 or more consecutive zeros.B3ZS is used to ensure a sufficient number of transitions to maintain system synchronization when the user data stream contains an insufficient number of "ones" to do so.
B6ZS: Bipolar 6 Zero Substitution
Bipolar 6 Zero Substitution (B6ZS) refers to a T-carrier Line Code in which bipolar violations are deliberately inserted if user data contains a string of 6 or more consecutive zeros. B6ZS is used to ensure a sufficient number of transitions to maintain system synchronization when the user data stream contains an insufficient number of "1s" to do so.
B8ZS: Bipolar 8 Zero Substitution
Bipolar 8 Zero Substitution (B8ZS) is a method of line coding used in the T-carrier system which allows full 64 Kbit/s per second per channel. On a T1, ones are sent by applying voltage to the wire, where a zero is sent by having no voltage on the wire. Sending eight zeros in a row could cause T1 equipment to lose synchronization with the sending equipment, it is important that that pattern is not sent.
Babble
Babble refers to noise or confusion, which is the aggregate crosstalk from interfering channels.
Backbone Cabling
Backbone Cabling refers to a portion of premises telecommunications cabling that provides connections between telecommunications closets, equipment rooms and entrance facilities. It consists of the transmission media (optical fiber cable), main and intermediate cross-connects, and terminations for the horizontal cross-connect, equipment rooms, and entrance facilities. Backbone cabling, sometimes called backbone wiring, can further be classified as inter-building backbone (cabling between buildings), or intrabuilding backbone (cabling within a building).
Back-Channel
Back-channel is, in an asymmetric telecommunications system, typically a low-speed or less-than-optimal transmission channel opposite to the main channel's direction. An example of this is in ADSL where "A" stands for "asymmetric", and the channel from the subscriber to the supplier is slower and may be of less capacity than the channel from the supplier to the subscriber.
Background Noise
Background Noise is the random signals that can be attributed to the unpredictable movement of free elections in a communication channel.
Back-Haul
Back-Haul is a communications path which takes traffic farther than the ultimate destination, then routes it back. This is done because the cost of transmission to the more remote location is much lower than a more direct route.
Back-to-Back Connection
Back-to-back connection is: 1. A direct connection between the output of a transmitting device and the input of an associated receiving device. When used for equipment measurements or testing purposes, such a back-to-back connection eliminates the effects of the transmission channel or medium. 2 . A direct connection between the output of a receiving device and the input to a transmitting device. The term "direct," as used in both definitions, may be construed as permitting a passive device such as a pad (attenuator) to accommodate power level constraints.
Backward Channel
Backward Channel is the channel in a data circuit that passes data in a direction opposite to that of its associated forward channel. The backward channel is usually used for transmission of request, supervisory, acknowledgement, or error-control signals. The direction of flow of these signals is opposite to that in which user information is being transferred. The backward-channel bandwidth is usually less than that of the primary channel, that is, the forward (user information) channel. For example, ADSL's upstream channel, considered a backward channel for some types of analysis, typically has a bandwidth less than one-fourth of the downstream channel.
In data transmission, it is a secondary channel in which the direction of transmission is constrained to be opposite to that of the primary, i.e., the forward (user-information) channel. The direction of transmission in the backward channel is restricted by the control interchange circuit that controls the direction of transmission in the primary channel.
Backward Signal
Backward signal is a signal sent from the called to the calling station, i.e., from the original data sink to the original data source. Backward signals are usually sent via a backward channel and may consist of supervisory, acknowledgment, or control signals.
BAF: Bellcore AMA Format
Bellcore AMA Format (BAF) is a system of abstract syntax and semantics that supports coding of Automatic Message Accounting (AMA) data into records.
Balance Return Loss
Balance Return Loss refers to the following two definitions in telecmmunication: (1) A measure of the degree of balance between two impedances connected to two conjugate sides of a hybrid set ( a functional unit in which more than two different technologies are combined to satisfy a given requirement ), coil, network, or junction. (2) A measure of the effectiveness with which a balancing network simulates the impedance of a two-wire circuit at a hybrid coil ( a single transformer that effectively has three windings, and which is designed to be configured as a circuit having four branches, e.g., ports, that are conjugare in pairs).
Balanced Impedance
Balanced Impedance is the state of impedance on a two-wire line when the impedance to ground as measured from one wire is equal to the impedance to ground as measured from the other wire. A balancing network is a combination of electronic components which stimulate the impedance of a uniform cable or open-wire circuit over a band of frequencies.
Balanced Line
Balanced Line is a transmission line consisting of two conductors in the presence of ground, capable of being operated in such a way that when the voltages of the two conductors at all transverse planes are equal in magnitude and opposite in polarity with respect to ground, the currents in the two conductors are equal in magnitude and opposite in direction.
Ballot
Ballot, also know as a Letter Of Agency(LOA), is a release form in telecommunication system used to authorizes a customer's long-distance phone service to be switched to (another) long-distance carrier, or reseller.
BAN: Billing Account Number
Billing Account Number (BAN) is an account number used by telephone companies to designate a customer or customer location that will be billed. A single customer may have multiple billing accounts.
Band
Band in telecommunication refers to the following definitions: 1. The range of frequencies between two defined limits which are used for a specific purpose. 2. One of the geopolitical boundaries established to define a WATS (wide-area telephone service) serving area.
Band Elimination Filter
Band Elimination Filter is an electrical device which blinds a receiving unit from recognizing a specific range of frequencies.
Banded Rates
Banded Rates is tariffed rates that may be changed by the telecom carrier within a specified range. Frequently, state commissions require notice to the commission prior to each change. Banded rates are being used less frequently today.
Bandwidth Cap
Bandwidth Cap refers to a bandwidth limitation, which is administered by an Internet service provider (ISP), that limits the transfer of a specified amount of data over a period of time. If a user exceeds the bandwidth cap, the ISP restricts connection speed or other services. The ISP may offer the purchase of additional bandwidth. Another type of bandwidth cap, also administrated by an ISP, is one which limits the speed of data transfer on a broadband Internet connection. Though the term is used in some cases and not on others, a bandwidth cap is not correctly considered a limit of speed.
Bandwidth Compression
Bandwidth Compression is: 1. the reduction of the bandwidth needed to transmit a given amount of data in a given time. 2. the reduction of the time needed to transmit a given amount of data in a given bandwidth.
Bandwidth Limited Operation
Bandwidth Limited Operation refers to the condition of telecommunication system under which the limitation on performance is imposed by the system bandwidth. The condition is reached when modal dispersion distorts the shape of the waveform beyond specified limits.
Bandwidth Throttling
Bandwidth throttling is a method of ensuring a bandwidth intensive device, such as a server, to limit ("throttle") the number of requests it will respond to within a specified period of time. Bandwidth throttling helps providing quality of service (QoS) by limiting network congestion and server crashes.
Basic Service
Basic Service refers to the minimum set of capabilities which are necessary for use of the public telecommunications network. Current basic service includes an access line, with access to local and long distance calling, to emergency calling (911), and to voice/non-voice relay service.
BCC: Block Check Character
Block Check Character (BCC) is a character added to a telecommunication transmission block to facilitate error detection. In longitudinal redundancy checking and cyclic redundancy checking, block check characters are computed for, and added to, each message block transmitted. This block check character is compared with a second block check character computed by the receiver to determine whether the transmission is error free
BCD: Binary Coded Decimal
Binary Coded Decimal (BCD) refers to a binary equivalent of the decimal system which also occupies a nibble. In BCD, the binary patterns 1010 through 1111 do not represent valid BCD number, and cannot be used.
BCH Code: Bose, Ray-Chaudhuri, Hocquenghem Code
Bose, Ray-Chaudhuri, Hocquenghem (BCH) Code is a multilevel, cyclic, error-correcting, variable-length digital code used to correct errors up to approximately 25% of the total number of digits. BCH codes are not limited to binary codes, but may be used with multilevel phase-shift keying whenever the number of levels is a prime number or a power of a prime number. A BCH code in 11 levels has been used to represent the 10 decimal digits plus a sign digit. BCH codes make use of field theory and polynomials over that field. The way the check polynomial is constructed provides the key to indicating that an error has occurred.
B-Channel Bundling
B-Channel Bundling, also known as bearer channel bundling, refers to a technique used to squeeze more voice conversations onto a single line in ISDN. The B channel, one of the fundamental components of the ISDN interface, is circuit-switched and can carry 64,000 bps of voice or data in either direction. B-channel bundling is based on Digital Speed Interpolation (DSI), in which speech is sliced up so that bits are transmitted only when someone is speaking.
BDCS: Broadband Digital Cross-Connect System
Broadband Digital Cross-Connect System (BDCS) is a SONET DCS capable of cross-connecting DS-3, STS-1 and STS-3c signals.
Bell Customer Code
Bell Customer Code is a three-digit numeric code, appended to the end of the Main Billing Telephone Number, that is used by Local Exchange Carriers to provide unique identification of customers.
Bellcore
Bellcore, now called Telcodia, was established by the former AT&T divestiture, representing and funded by the Regional Bell Carriers RBOCs. The organization establishes telephone-network standards, training materials and quality procedures.
BER: Bit Error Rate
Bit Error Rate (BER) is the ratio of received bits that contain errors. BER is usually expressed as ten to a negative power. For example, a transmission might have a BER of 10 to the minus 9, which indicates that, out of a billion bits transmitted, one bit was in error. Typically, the bits in error need to be re-transmitted, which may slow down communications.
BERT: Bit Error Rate Tester
Bit Error Rate Tester (BERT) is the device that determines the Bit Error Rate (BER) on a given communications channel.
Bent Pipe Technology
Bent Pipe Technology refers to satellite technology to transmit calls from one point on Earth to a satellite and back down to another point on Earth.
BHCA: Busy Hour Call Attempt
Busy Hour call Attempt (BHCA) is the number of times a telephone call is attempted during the busiest hour of the day.
BIB: Backward Indicator Bit
Backward Indicator Bit (BIB), a one-bit field in the SS7 Message Signaling Unit (MSU), indicates a negative acknowledgment by the remote signaling point when toggled.
Bidirectional Switch
Bidirectional Switch is a switch in which a moving contact level travels in two directions to connect to a desired fixed contact. While the most common combination is a vertical motion followed by an angular motion, other combinations are possible.
Bifurcated
Bifurcated, in a telecommunication network, refers to a two-pronged connector. A "bifurcated wire wrap" terminal block is one that has an "H" shape, which forms one electrical connection pair with two connection terminals.
Billboard Antenna
Billboard Antenna is an array of parallel dipole antennas with flat reflectors, usually positioned in a line or plane. The spacing and dimensions of the dipoles depend on the wavelength. The main lobe of a fixed billboard antenna may, within limits, be steered by appropriate phasing of the respective signals to individual elements of the array.
Bill-To-Room
Bill-To-Room is a billing option associated with Operator Assisted calls that allows the calling party to bill a call to their hotel room. With this option, the carrier is required to notify the hotel, upon completion of the call, of the time and charges.
Binary Golay Code
Binary Golay Code refers to two so-called closely related error-correcting codes. One is called extended binary Golay code which is an error-correcting code that encodes 12 bits of data in a 24-bit word in such a way that any triple-bit error can be corrected and any quadruple-bit error can be detected. The other is called perfect binary Golay Code which has odewords of length 23 and is obtained from the extended binary Golay code by deleting one coordinate position. Conversely, the extended binary Golay code can be obtained from the perfect binary Golay Code by adding a parity bit.
Binary Signal
Binary Signal is a signal that may assume either of two polarities, neither of which is zero. A bipolar signal may have a two-state non-return-to-zero (NRZ) or a three-state return-to-zero (RZ) binary coding scheme. A bipolar signal is usually symmetrical with respect to zero amplitude, i.e., the absolute values of the positive and negative signal states are nominally equal.
Binary Switch
Binary Switch is a switch that must exist in one of only two states: on/off, zero/one, etc.
Biphase Mark Code
Biphase Mark Code is a type of encoding for binary data streams. If a binary data stream is sent without any modification via any channel, if there are long series of logical ones or zeros without any change, this can cause problems in synchronization. Streams encoded in NRZ are affected by the same problem. Using Biphase Mark Code makes synchronization easier.
Bipolar
Bipolar is a code or transmission scheme incorporating both negative and positive polarity pulses. In AT&T's DDS bipolar transmission scheme, a negative-positive pulse and the absence of pulses indicates a binary zero. In this code, bipolar violation occurs when the alternating negative-positive pulsating pattern of the bipolar code is not followed.
Bipolar Encoding
Bipolar encoding is a type of line code (a method of encoding digital information to make it resistant to certain forms of signal loss during transmission). A binary 0 is encoded as zero volts as in unipolar encoding. A binary 1 is encoded alternately as a positive voltage and a negative voltage. This prevents a significant build-up of DC, as the positive and negative pulses average to zero volts. Little or no DC-component is considered an advantage because the cable may then be used for longer distances and to carry power for intermediate equipment such as line repeaters. The DC-component can be easily and cheaply removed before the signal reaches the decoding circuitry.
Bipolar Signal
Bipolar Signal is a baseband method of sending binary data over wire or cable. It is also called bipolar transmission. There are two logic states, low and high, represented by the digits 0 and 1 respectively.
Bipolar Violation
Bipolar violation refers to an error occurred during the transmission of a T1 signal where two pulses of the same polarity take places without an intervening pulse of the opposite polarity.
BISYNC: Binary Synchronous Communications
Binary Synchronous Communications (BISYNC) is a character (byte)-oriented form of communication developed by IBM in the 1960s. It was originally designed for batch transmissions between the IBM S/360 mainframe family and IBM 2780 and 3780 terminals. It supports online and RJE (remote job entry) terminals in the CICS/VSE (Customer Information Control System/Virtual Storage Extended) environment.
Bit Pairing
Bit Pairing refers to the practice of establishing, within a code set, a number of subsets that have an identical bit representation except for the state of a specified bit. An example of bit pairing takes place in the International Alphabet No. 5 and the American Standard Code for Information Interchange (ASCII), where the upper case letters are related to their respective lower case letters by the state of bit six.
Bit Slip
Bit Slip refers to the loss of a bit or bits caused by variations in the respective clock rates of the transmitting and receiving devices. One cause of bit slippage is overflow of a receive buffer that occurs when the transmitter's clock rate exceeds that of the receiver. This causes one or more bits to be dropped for lack of storage capacity.
Bit Stuffing
Bit Stuffing refers to the the practice of inserting non-information of bits to a stream of data. Bit stuffing is required by many network and communications protocols for the following reasons:
1. To prevent data being interpreted as control information. For instance, many frame-based protocols, such as X.25, signal the beginning and end of a frame with six consecutive 1 bits. Therefore, if the actual data being transmitted has six 1-bits in a row, a zero is inserted after the first 5 so that the dat is not interpreted as a frame delimiter. Of course, on the receiving end, the stuffed bits must be discarded.
2. For protocols that require a fixed-size frame, bits are sometimes inserted to make the frame size equal to this set size.
3. For protocols that required a continuous stream of data, zero bits are sometimes inserted to ensure that the stream is not broken.
Bit Synchronous
Bit Synchronous is a data transmission technique in which each bit is synchronized against an accurate clock. In asynchronous transmission, this synchronization is held for one character. In synchronous transmission, this synchronization is held for a block of characters.
Bit-Count Integrity
Bit-count integrity, in telecommunication, has the following meanings: 2. In message communications, the preservation of the exact number of bits that are in the original message. 2. In connection-oriented services, preservation of the number of bits per unit time.
Biternary Transmission
Biternary Transmission refers to the digital transmission in which two binary pulse trains are combined for transmission over a channel in which the available bandwidth is sufficient for transmission of only one of the two pulse trains at a time if they remain in binary form.
BITS: Building Integrated Timing Supply
Building Integrated Timing Supply (BITS) is a clock in a central office that supplies DS1 and/or composite clock timing references to all synchronous network elements in that office.
Black Noise
Black noise refers to noise that has a frequency spectrum of predominantly zero power level over all frequencies except for a few narrow bands or spikes. An example of black noise in a facsimile transmission system is the spectrum that might be obtained when scanning a black area in which there are a few random white spots. Thus, in the time domain, a few random pulses occur while scanning.
Black Recording
Black recording refers to the following definition in facsimile system of telecommunication: 1. if it uses amplitude modulation, recording in which the maximum received power corresponds to the maximum density of the record medium. 2. if it uses frequency modulation, recording in which the lowest received frequency corresponds to the maximum density of the record medium.
Blind Transmission
Blind Transmission refers to the transmission without obtaining a receiving acknowledgement of reception from the intended receiving station. Blind transmission may occur or be necessary when security constraints, such as radio silence, are imposed, when technical difficulties with a sender's receiver or receiver's transmitter occur, or when lack of time precludes the delay caused by waiting for receipts.
B-Link: Bridge-Link
SS7 Bridge-link(B-link) connects a STP to another STP. Typically, a quad of B-links interconnect peer (or primary) STPs (e.g., the STPs from one network to the STPs of another network). The distinction between a "B" link and a "D" link is rather arbitrary. For this reason, such links may be referred to as "B/D" links.
Blocked Attempt
Blocked Attempt refers to an attempt that cannot be further advanced toward its destination due to an equipment shortage or failure in the network.
Blocking
Blocking in telecommunication refers to the inability of the calling party to be connected to the called party be cause either: 1. All permitted trunk paths are busy. 2. A path between a given inlet and any permitted free outlet of the switching network of a switching system is unavailable
Blocking Probability
Blocking probability is the statistical probability that a telephone connection cannot be established due to insufficient transmission resources in the network. Blocking probability is usually expressed as a percentage or decimal equivalent of calls blocked by network congestion during the busy hour.
BOC: Bell Operating Company
Bell Operating Company (BOC ) refers to any of the 22 original companies (or their successors) that were created when AT&T was broken up in 1983 and given the right to provide local telephone service in a given geographic area. The companies had previously existed as subsidiaries of AT&T and were called the "Bell System." The purpose of the breakup was to create competition at both the local and long-distance service levels. BOCs compete with other independent companies to sell local phone service. In certain areas, long-distance companies, including AT&T, can now compete for local service. Collectively, companies offering local phone service are referred to as local exchange carriers.
BPON: Broadband Passive Optic Network
Broadband Passive Optic Network (BPON), originally called ATM Passive Optic Network (APON), is the initial PON specifications defined by the FSAN committee used ATM as their layer 2 signaling protocol. Use of the term APON led users to believe that only ATM services could be provided to end-users, so the FSAN decided to broaden the name to Broadband PON (BPON). BPON systems offer numerous broadband services including Ethernet access and video distribution.
BPV: Bipolar Violation
Bipolar Violation (BPV) is a Error Event in the DS1/T1 interface for an AMI-coded signal is the occurrence of a pulse of the same polarity as the previous pulse. A BPV error event for a B8ZS- or HDB3-coded signal is the occurrence of a pulse of the same polarity as the previous pulse without being a part of the zero substitution code.
BRAS: Broadband Remote Access Server
Broadband Remote Access Server (BRAS) is the aggregation point for the subscriber traffic. It provides aggregation capabilities (e.g. IP, PPP, ATM) between the Regional/Access Network and the NSP or ASP. Beyond aggregation it is also the injection point for policy management and IP QoS in the Regional/Access Networks.
BRI: Basic Rate Interface
Basic Rate Interface (BRI) is an ITU-T ISDN multipurpose user interface standard for simultaneous voice and data services provided over two 64-kb/s bearer channels and one 16-kb/s data channel (2B+D) access arrangement to each user location. The B channels are used for voice or user data, and the D channel is used for any combination of: data, control/signalling and X.25 packet networking. The two B channels can be bonded together giving a total data rate of 128 kbit/s. BRI is the kind of ISDN interface most likely to be found in residential service.
BR-ISDN: Basic Rate ISDN
Basic Rate ISDN (BR-ISDN or BRI) refers to one of the two levels of services in ISDN called Basic Rate Interface which is intended for the home and small enterprise, while the other service is called Primary Rate Interface (PRI), for larger users. Both rates include a number of B-channels and a D-channel. Each B-channel carries data, voice, and other services. The D-channel carries control and signaling information. The Basic Rate Interface consists of two 64 Kbps B-channels and one 16 Kbps D-channel. Thus, a Basic Rate Interface user can have up to 128 Kbps service. The Primary Rate Interface consists of 23 B-channels and one 64 Kpbs D-channel in the United States or 30 B-channels and 1 D-channel in Europe.
Broadband Internet Access
Broadband Internet Access is a high data-transmission rate Internet connection. DSL, ADSL, Wireless WAN and cable modem, all popular consumer broadband technologies, are typically capable of transmitting 256 kilobits per second or more, starting at approximately four times the speed of a modem using a standard digital telephone line.
Broadband Open Access
Broadband open access refers to the policy in broadband Internet access, which means that the owner of a network must make it available to all users under the same terms and conditions. The network owner cannot interfere with the content that travels over the network. By contrast, in a closed network, the network owner can prevent anyone it wants to from using the network, can determine what traffic it will or won't carry, and can set priorities based on where the traffic comes from or to whom it's going (or for any other reason).
The telephone network is an "open access" or "open" network. As a result of this openness the Internet grew and flourished. Any internet service provider (ISP) who wants to offer service can do so, despite the fact that the phone companies that own the lines offer competing services.
The FCC itself has acknowledged the importance of an open network in the development and growth of Internet.
Broadband Telephony
Broadband Telephony refers to the utilization of broadband data connections to deliver voice calls. Typically, services are hosted that means customers enjoy traditional phone functionality without the need to purchase a phone system. Calls are transmitted as IP Packets to the host company, where they either 'break out' to the public networks, or continue as IP calls across the Internet.
BSE: Basic Service Element
Basic Service Element(BSE) refers to 1. an optional unbundled feature, generally associated with the basic serving arrangement (BSA), that an enhanced-service provider (ESP) may require or find useful in configuring an enhanced service. 2. a fundamental communication network service; an optional network capability associated with a BSA. BSEs constitute optional capabilities to which the customer may subscribe or decline to subscribe.
BSN: Backward Sequence Number
Backward Sequence Number (BSN) is a 7 bits field in the SS7 Message Signaling Unit (MSU) that acknowledges the receipt of signal units by the remote signalling point. It contains the sequence number of the signal unit being acknowledged.
BT Group
BT Group refers to British Telecommunications pls which is the privatized UK state telecommunications operator. It is the dominant fixed line telecommunications provider in the UK.
Busy Hour
Busy Hour refers to a consecutive 6-minute interval with the highest levels of measurement or derived load used in traffic engineering. A busy hour may also be identified by the period of the day, the class of service of the traffic, and so on, e.g., morning busy hour, coin busy hour.
Busy Signal
Busy Signal is a signal that is used in Public Switched Telephone Networks to indicate that the called party is already taking another call. In most switching systems, the busy signal will be emitted until the caller goes on-hook
Busy Tone
Busy Tone is a single tone that is repeated at a 60ipm (impulse per minute) rate to indicate that a call's terminating location is already in use.
Busy Verification Tone
Busy Verification Tone is a Centrex feature that allows the attendant to call and be connected to a busy Centrex station within the attendant's customer group. The busy verification tone is applied to both parties of the connection to inform them of the intrusion by the attendant. No tone is applied if the station called for busy verification is idle.
Bypass Trunk Group
Bypass Trunk Group is a trunk group, in a hierarchical network, (usually high usage) that circumvents one or more tandems in its routing ladder.