| Glossary: B |
| B3ZS |
See Bipolar Three Zero Substitution. |
| Bandpass filter |
A circuit designed to allow only frequencies within a specific range to pass. The cutoff frequencies must be finite and nonzero. The band of frequencies between the cutoff frequencies is the passband. |
| Bandwidth |
The range of frequencies available for signaling; the difference between the highest and lowest frequencies of a band, expressed in hertz. |
| Baseband |
Describing the band of frequencies occupied by a signal below the point that the signal is modulated as an analog carrier frequency. |
| Baud |
A unit of modulation rate, equal to the maximum number of signal events or symbols that can be transmitted per second. A signal event is a change in an information-bearing signal or waveform, which represents some number of encoded bits. The term baud should not be used as a synonym for bits per second (though many people do) since at speeds above 2,400 bits per second multiple bits are sent in each baud and, therefore, the baud rate does not equal the bit rate. |
| BECN |
Backward Explicit Congestion Notification |
| Benchmark |
A value used for comparison. For example, when a circuit is first put into service, it is tested for its transmission characteristics. These values are typically recorded and used for comparison when later testing becomes necessary on that circuit. |
| BER |
Bit Error Ratio or Rate |
| BERT |
Bit Error Rate Test |
| Binary digit |
The smallest entity of digital information possible. |
| BIP |
Bit Interleaved Parity |
| Bipolar |
A 2-state code where successive "1" signals alternate between positive and negative polarity. |
| Bipolar coding |
A T-carrier line-coding system. This system alternates the polarity of consecutive ones bits. (See AMI, B8ZS, and B3ZS.) |
| Bipolar eight zeros substitution (B8ZS) |
A line-code in which eight consecutive zeros are replaced with a unique signature, either 000+-0-+ if the preceding pulse was positive, or 000-+0+- if the preceding pulse was negative. Bit positions 4 and 7 will always be BPVs. |
| Bipolar return-to-zero (BPRZ) |
A 3-level code in which alternate ones change in sign. (For example, 1011 becomes +1, 0, -1, +1.) Also, transitions between adjacent ones pause at the zero voltage level. |
| Bipolar three-zeros substitution (B3ZS) (also designated HDB2 and HDB3) |
Each block of 3 (or 4) successive zeros is replaced by 00V (or 000V respectively) or B0V (B00V). The choice of 00V (000V) or B0V (B00V) is made so that the number of B pulses between consecutive V pulses is odd. In other words, successive V pulses are of alternate polarity so that no dc component is introduced. |
| Bipolar violation |
A condition which occurs when an AMI-coded signal contains a pulse of the same polarity as the previous pulse and which is not part of a bipolar zero substitution code (e.g., B8ZS for a DS1 signal or B3ZS for a DS3 signal). |
| BPV |
A condition which occurs when an AMI-coded signal contains a pulse of the same polarity as the previous pulse and which is not part of a bipolar zero substitution code (e.g., B8ZS for a DS1 signal or B3ZS for a DS3 signal). |
| Bipolar violation ratio |
The number of accumulated BPVs in the last monitored interval divided by the number of bits in that interval. Any one second where there is an LOS condition is not included in this computation. |
| Bis |
ITU terminology indicating a second formal release of an existing communications recommendation. Derived from the French and Latin word for “second” (or for the second time). For example, V.32 bis is the first enhancement (second version) of the V.32 recommendation. |
| Bisync |
Binary synchronous communication |
| Bisync (binary synchronous communication) |
A half-duplex, character-oriented data communications protocol originated in 1964. It includes control characters and procedures for controlling the establishment of a valid connection and the transfer of data. Although still enjoying widespread usage, it is being replaced by the more efficient protocol, Synchronous Data Link Control (SDLC). |
| Bit |
Contraction of Binary Digit. The smallest unit of information in a binary system; a one or zero condition. |
| Bit error |
The bit received in the data pattern is different from the bit expected, showing that the value of a bit has changed during transmission. When a bit error occurs, the receiving end receives the bit incorrectly. |
| Bit error count |
The total number of bit errors counted during a timed interval. |
| Bit error ratio (BER) |
A measure of transmission quality, expressed as a ratio. The BER indicates how many bits are errored (incorrectly received) in a given bit stream. Generally notated as a negative exponent. For example, 1 x 10E -7 indicates one out of ten million bits (1 of 10, 000,000) are in error. Although a ratio, it is commonly referred to as “bit error rate." |
| Bit robbing |
The technique used to allow the digital data in the DS1 stream to carry the signaling and supervision. The least significant bit per channel in every sixth frame carries the signaling. |
| Bit stuffing |
The process of adding extra bits to the outgoing customer data. These bits permit synchronization and signaling. |
| BITS |
Building Integrated Timing System |
| Bits per second (BPS) |
Basic unit of measurement for serial data transmission capacity; abbreviated as kbps, or kilobits, for thousands of bits per second; Mbps, or megabits, for millions of bits per second; and Gbps, or gigabits, for billions of bits per second. |
| BITSCLK |
Building Integrated Timing Supply Clock Interface |
| Block error |
One or more bits in a 1-second window are in error (for DDS). Block size varies for other applications. |
| Blue alarm |
Notifies facilities at the receive end of a circuit that a red alarm has occurred upstream in the circuit. Also called an alarm indication signal (AIS). |
| BNC |
Bayonet Neill-Concelman (connector named for inventor). A bayonet-locking connector for slim coaxial cables, like those used with Ethernet. |
| BOC |
Bell Operating Company |
| BPNRZ |
Bipolar Non-Return-to-Zero |
| BPV code |
A specific BPV sequence purposely introduced to the local loop for network control. |
| BPV count |
The total number of BPVs counted during a timed test interval. |
| BPV rate |
The rate of erroneous received data bits to total received data bits. This rate excludes framing bits, CRC-6 bits, or data link bits. |
| BRCS |
Business and Residence Custom Services |
| BRI |
Basic Rate Interface |
| Bridging connection |
A parallel connection that draws some of the signal energy from a circuit, often with inconsequential effect on the circuit's operation. |
| Broadband |
Networking technique for transmitting large amounts of voice, data, image, and multimedia signals over long distances on coaxial or fiber optic cables; in digital communication, signals at the 45 Mbps or higher rate. |
| BRTU |
See Broadband Remote Test Unit |
| BRTU (Broadband Remote Test Access Unit) |
The 6750 BRTU is Hekimian's flagship digital test system. This single platform combines DS3, DS1, channelized analog, and channelized digital test capabilities for asynchronous and SONET circuits. The 6750 BRTU also serves as an interface to the PVS Logical Test system for DS1 and DS0 services. |
| Burst Errored Second |
A one-second period in which at least 100 bit errors have occurred or a one-second period in which more than one but fewer than 320 CRC-6 errors have occurred. |
| Bursty seconds (DS3 BS) |
A count of seconds with more than one (B3ZS) coding violation but fewer than 44 coding violations with no severely errored framing signal nor alarm indication signal conditions present. |
| BVP |
Beta Verification Platform |
| Byte |
A group of eight consecutive binary digits associated with a single user. A byte is typically the smallest addressable unit of information in a database or memory. |
| Byte stuffing |
A technique which increases the speed of a digital stream by repeating bytes and transmitting them at a faster rate. This technique does not increase the information content of the stream. |
