omniomni/omni-engineering huggingface dataset:
Backward channel. In a data transmission circuit a backward channel is the channel 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.

See also 
 Return channel

References

Federal Standard 1037C
MIL-STD-188

Data transmission
Bilateral synchronization. In telecommunications, bilateral synchronization (or bilateral control) is a synchronization control system between exchanges A and B in which the clock at telephone exchange A controls the data received at exchange B and the clock at exchange B controls the data received at exchange A.  

Bilateral synchronization is usually implemented by deriving the timing from the incoming bitstream.

Source: from Federal Standard 1037C in support of MIL-STD-188

See also 
 Plesiochronous digital hierarchy

Synchronization
Bit-count integrity. In telecommunications, the term bit-count integrity (BCI) has the following meanings: 

In message communications, the preservation of the exact number of bits that are in the original message.
In connection-oriented services, preservation of the number of bits per unit time.

Note:  Bit-count integrity is not the same as bit integrity, which requires that the delivered bits correspond exactly with the original bits.

Source: from Federal Standard 1037C and from MIL-STD-188

Data transmission
Bit inversion. In computing and telecommunications, bit inversion means the changing of the state of a bit or binary number to the opposite state, i.e. the changing of a 0 bit to 1 or of a 1 bit to 0. It is often represented with a tilde (~). It also refers to the changing of a state representing a given bit to the opposite state.

References

See also 
 Bitwise operation
 Bit error
 Two's complement

Data transmission
Bit pairing. In telecommunications, bit pairing is 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.  

Note:  An example of bit pairing occurs 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.

References 

Data transmission
Bit-sequence independence. In telecommunications, bit-sequence independence is a characteristic of some digital data transmission as well as  digital transmission systems that impose no restrictions on, or modification of, the transmitted bit sequence.

Bit-sequence-independent protocols are in contrast to protocols that reserve certain bit sequences for special meanings, such as the flag sequence, 01111110, for HDLC, SDLC, and ADCCP protocols.

Bit-sequence-independence allows only line codes that have the same number of transitions per bit, otherwise, the line code is dependent on the bit sequence and, therefore, bit-sequence dependent.

References

Telecommunication theory
Bit-synchronous operation. Bit-synchronous operation is a type of digital communication in which the data circuit-terminating equipment (DCE), data terminal equipment (DTE), and transmitting circuits are all operated in bit synchronism with a clock signal.

In bit-synchronous operation, clock timing is usually delivered at twice the modulation rate, and one bit is transmitted or received during each clock cycle.

Bit-synchronous operation is sometimes erroneously referred to as digital synchronization.

References

Line codes
Bonding. Bonding may refer to:

Arts and entertainment
 Bonding (TV series), a 2019 Netflix Original TV series
 "Bonding" (Kim Possible), a 2004 episode of the television series Kim Possible
 "The Bonding", a 1989 episode of the television series Star Trek: The Next Generation
 The Bonding (album), a 2013 album by Austrian symphonic metal band Edenbridge

Other uses
 Bonding (dental), a dental procedure in which a dentist applies a resin material to the tooth

See also
 Human bonding
 Female bonding
 Male bonding
 Channel bonding (or modem bonding), an arrangement in which two or more network interfaces on a host computer are combined
 NIC bonding, an alternate name for link aggregation
 Electrical bonding, practice of connecting all metal objects in a room to protect from electric shock
 Bonding, a method for creating electric interconnects:
 Ball bonding, a method very similar to wire bonding
 Chip bonding, a method of wiring some chips (also from different manufactures) together on die an integrated circuit
 Wire bonding, a method of making interconnections between a microchip and the outside world as part of semiconductor device fabrication
Bridging loss. Bridging loss is the loss, at a given frequency, that results when an impedance is connected across a transmission line. It is expressed as the ratio, in decibels, of the signal power delivered to a given point in a system downstream from the bridging point prior to bridging, to the signal power delivered to the given point after bridging. The term is introduced because return loss is not applicable to the high-impedance input conditions. The term is also used in telephone practice and is synonymous with the insertion loss that results from bridging an impedance across a circuit.

References 

Source: from Federal Standard 1037C and from MIL-STD-188

Electrical parameters
Buffer. Buffer may refer to:

Science
 Buffer gas, an inert or nonflammable gas
 Buffer solution, a solution used to prevent changes in pH
 Lysis buffer, in cell biology
 Metal ion buffer
 Mineral redox buffer, in geology

Technology and engineering
 Buffer (GIS), a HASS zone around a map feature
 Buffer (optical fiber), a GG component of a fiber optic cable
 Buffer (rail transport), a device that cushions impacts between vehicles
 Buffer amplifier, an isolating circuit used in electronics or telecommunications
 Buffer stop, a device that keeps rail vehicles on tracks
 Buffer wheel, a device used to smooth a workpiece's surface
 Digital buffer, an electronic circuit used to isolate the input from the output
 Floor buffer, an appliance used to polish hard floors
 Optical buffer, a device that stores optically transmitted data
 Recoil buffer, a firearm component
 Seismic buffers, protect structures against the effects of earthquakes

Computing
 Buffer (application), a software application for managing social network accounts
 Data buffer, memory used temporarily to store output or input data while it is transferred.
 Framebuffer, a type of data buffer for use in graphical display
 Memory buffer register, the connection between processor and memory

People
 Bruce Buffer (born 1957), American sports announcer for UFC events
 Michael Buffer (born 1944), American ring announcer for boxing and wrestling events

Other uses
 Buffer (navy), a colloquial title
 Buffer state, a country separating two rival or hostile powers, thought to prevent conflict between them
 Buffer zone, a region separating two areas, possibly to segregate or conjoin them
 Buffering (horse), an Australian thoroughbred
 Buffering (TV series), a British TV series

See also
 Buff (disambiguation)
Call-second. In telecommunications, a call-second is a unit used to measure communications traffic density, equivalent to one call with a duration of one second. 

Traffic is measured independent of users. For example, one user making two 75-second calls is equivalent to two users each making one 75-second call, as each case produces 150 call-seconds of traffic. 

A CCS (centacall-second) is often used to describe 100 call-seconds, so 3600 call-seconds = 36 CCS = 1 call-hour. 

In a communication network, a trunk (link) can carry numerous concurrent calls by means of multiplexing. Hence a particular number of call-seconds can be carried in infinitely many ways as calls are established and cleared over time.  For example, one call-hour could be one call for an hour or two (possibly concurrent) calls for half an hour each. Call-seconds give a measure of the average number of concurrent calls.

Offered load is defined as the traffic density per unit time, measured in erlangs. An erlang is defined as one call-hour per hour, or 3,600 call-seconds per hour.

Hence, if one CCS is measured over a one-hour period, the offered load is 1/36 erlangs.

References

Units of measurement
Telecommunications
Carrier system. A carrier system is a communications system that transmits information, such as the voice signals of a telephone call and the video signals of television, by modulation of one or multiple carrier signals above the principal voice frequency or data rate.

Carrier systems typically transmit multiple channels of communication simultaneously over the shared medium using various forms of multiplexing. Prominent multiplexing methods of the carrier signal are time-division multiplexing (TDM) and frequency-division multiplexing (FDM). A cable television system is an example of frequency-division multiplexing. Many television programs are carried simultaneously on the same coaxial cable by sending each at a different frequency. Multiple layers of multiplexing may ultimately be performed upon a given input signal. For example, in the public switched telephone network, many telephone calls are sent over shared trunk lines by time-division multiplexing. For long-distance calls several of these channels may be sent over a communications satellite link by frequency-division multiplexing. At a given receiving node, specific channels may be demultiplexed individually.

History 
The purpose of carrier systems is to save money by carrying more traffic on less infrastructure.  19th century telephone systems, operating at baseband, could only carry one telephone call on each wire, hence routes with heavy traffic needed many wires.

In the 1920s, frequency-division multiplexing could carry several circuits on the same balanced wires, and by the 1930s L-carrier and similar systems carried hundreds of calls at a time on coaxial cables.

Capacity of these systems increased in the middle of the century, while in the 1950s researchers began to take seriously the possibility of saving money on the terminal equipment by using time-division multiplexing. This work led to T-carrier and similar digital systems for local use.

Due to the shorter repeater spacings required by digital systems, long-distance still used FDM until the late 1970s when optical fiber was improved to the point that digital connections became the cheapest ones for all distances, short and long. By the end of the century, analog connections between and within telephone exchanges became rare.

See also
 Channel access method

References

External links
 J-carrier

Multiplexing
Channel service unit. In telecommunications, a channel service unit (CSU) is a line bridging device for use with T-carrier, which
is used to perform loopback testing;
may perform bit stuffing;
may also provide a framing and formatting pattern compatible with the network;
provides a barrier for electrical interference from either side of the unit; and
is the last signal regeneration point, on the loop side, coming from the central office, before the regenerated signal reaches a multiplexer or data terminal equipment (DTE).

Common varieties 
CSUs can be categorized by the class of service they support (DS1, DS3, DDS, etc.) and by the capabilities within that class. For example, basic DS1 (T1) CSUs support loopback of each interface and will produce alarm indication signal to the provider's network interface device (NID) in the event of loss of signal from the customer-premises equipment (CPE). More advanced units will include internal monitors of the performance of the carrier in both directions and may have test pattern generation and monitor capabilities.

Common practice 
CSUs are required by PSTN providers at digital interfaces that terminate in a DSU on the customer side. They are not used when the service terminates in a modem, such as the DSL family of service. The maintenance capabilities of the CSU provide important guidance as to whether the provider needs to dispatch a repairman to the customer location.

See also 
 CSU/DSU

References

Telecommunications equipment
Circuit restoration. In telecommunications, circuit restoration is the process by which a communications circuit is established between two users after disruption or loss of the original circuit.  The loss may be widespread due to a natural disaster like an ice storm or hurricane, or local by being cut underground in construction or damaged in a thunderstorm or car accident.

Circuit restoration is usually performed in accordance with planned procedures and priorities. Restoration may be effected automatically, such as by switching to a hot standby, or manually, such as by manual patching.

Communication circuits
Cladding. Cladding is an outer layer of material covering another. It may refer to the following:

Cladding (boiler), the layer of insulation and outer wrapping around a boiler shell
Cladding (construction), materials applied to the exterior of buildings
Wall cladding, exterior material applied to the walls of a building
Copper cladding, applying copper to the exterior of buildings
Rainscreen cladding, an exterior wall detail to create a capillary break and to allow drainage and evaporation of water
Cladding (fiber optics), fiber optics property to contain light in the core of the fiber by total internal reflection 
Cladding (metalworking), a bonding together of dissimilar metals
Cladding (nuclear fuel), the outer layer of the fuel rods, standing between the coolant and the nuclear fuel

See also 
CLAD (disambiguation)
Closed-loop transfer function. In control theory, a closed-loop transfer function is a mathematical function describing the net result of the effects of a feedback control loop on the input signal to the plant under control.

Overview 
The closed-loop transfer function is measured at the output. The output signal can be calculated from the closed-loop transfer function and the input signal.  Signals may be waveforms, images, or other types of data streams.

An example of a closed-loop block diagram, from which a transfer function may be computed, is shown below:

The summing node and the G(s) and H(s) blocks can all be combined into one block, which would have the following transfer function:

 

 is called the feed forward transfer function,  is called the feedback transfer function, and their product  is called the open-loop transfer function.

Derivation
We define an intermediate signal Z (also known as error signal) shown as follows:

Using this figure we write:

 

 

Now, plug the second equation into the first to eliminate Z(s):

Move all the terms with Y(s) to the left hand side, and keep the term with X(s) on the right hand side:

Therefore,

See also
Federal Standard 1037C
Open-loop controller

References 

Classical control theory
Cybernetics
Code conversion. In telecommunications, the term code conversion has the following meanings: 

1.  Conversion of signals, or groups of signals, in one code into corresponding signals, or groups of signals, in another code.  

2.  A process for converting a code of some predetermined bit structure, such as 5, 7, or 14 bits per character interval, to another code with the same or a different number of bits per character interval. 

In code conversion, alphabetical order is not significant.

References

Line codes
Code word (communication). In communication, a code word is an element of a standardized code or protocol. Each code word is assembled in accordance with the specific rules of the code and assigned a unique meaning. Code words are typically used for reasons of reliability, clarity, brevity, or secrecy.

See also 
 Code word (figure of speech)
 Coded set
 Commercial code (communications)
 Compartmentalization (information security)
 Duress code
 Error correction and detection
 Marine VHF radio
 Password
 Safeword
 Spelling alphabet

References

UNHCR Procedure for Radio Communication

External links 
 UNHCR Procedure for Radio Communication

Data transmission
Cryptography
Coding. Coding may refer to:

Computer science
 Computer programming, the process of creating and maintaining the source code of computer programs
 Line coding, in data storage
 Source coding, compression used in data transmission
 Coding theory
 Channel coding

Other uses 
 Coding (social sciences), an analytical process in which data are categorized for analysis
 Coding strand of DNA in molecular biology
 Legal coding, the process of creating summary or keyword data from a document in the legal profession
 Medical coding, representation of medical diagnoses and procedures in standard code numbers
 Number coding in Metro Manila, a road space rationing policy implemented in Metro Manila, Philippines, commonly referred to as "coding"
 Coding (therapy), alternative therapeutic methods used to treat addictions in the post-Soviet countries
 Queer coding

See also
 Code
 Entropy encoding
 Transform coding
Combined distribution frame. In telecommunications, a combined distribution frame (CDF) is a distribution frame that combines the functions of main and intermediate distribution frames and contains both vertical and horizontal terminating blocks.  

The vertical blocks are used to terminate the permanent outside lines entering the station. Horizontal blocks are used to terminate inside plant equipment. This arrangement permits the association of any outside line with any desired terminal equipment. These connections are made either with twisted pair wire, normally referred to as jumper wire, or with optical fiber cables, normally referred to as jumper cables. 

In technical control facilities, the vertical side may be used to terminate equipment as well as outside lines. The horizontal side is then used for jackfields and battery terminations.

References

Broadcast engineering
Telephony equipment
Common control. In telecommunications, common control is a principle of switching telephone calls in an automatic telephone exchange that employs shared control equipment which is attached to the circuit of a call only for the duration of establishing or otherwise controlling the call.  Thus, such control equipment need only be provided in as few units to satisfy overall exchange traffic, rather than being duplicated for every subscriber line.

In contrast, direct control systems have subsystems for call control that are an integral part of the switching network. Strowger exchanges are usually direct control systems, whereas crossbar, and electronic exchanges (including all stored program control systems) are common control systems. Common control is also known as indirect control or register control.

History 
Early semi-mechanical installations with common control components existed, for example rotary systems in Sweden and France in 1915, and the first panel switches in Newark, New Jersey, also in 1915.  The first large-scale, fully automatic, common control switching system deployed in commercial production service was the ATlantic central office in Omaha, Nebraska, a panel system cut over on December 10, 1921. Other panel offices for Kansas City and New York City (the PENnsylvania exchange) were in planning at the same time and opened shortly after.

In 1922, common control was introduced in Strowger-type step-by-step systems, resulting in the first installations of Director systems in Havanna, Cuba in 1924, and in London, England in 1927.

By the mid-1920s, common control ideas had extended to include marker systems for testing for idle trunks.

During the 1960s, common control exchanges became stored program control exchanges, and by the 1970s they used common-channel signaling in which the channels that are used for signaling are not used for message traffic (out of band signaling).

References 

Telephone exchange equipment
Common Management Information Service. The Common Management Information Service (CMIS) is the service interface specified in ITU-T Recommendation X.710, ISO/IEC International Standard 9595 that is employed by OSI network elements for network management. It defines the service interface that is implemented by the Common Management Information Protocol (CMIP) as specified in ITU-T Recommendation X.711, ISO/IEC International Standard 9596-1. CMIS is part of the Open Systems Interconnection (OSI) body of international network standards.

Note the term CMIP is sometimes used erroneously when CMIS is intended. CMIS/CMIP is most often used in telecommunications applications, in other areas SNMP has become more popular.

Services
The following services are made available by the Common Management Information Service Element (CMISE) to allow management of network elements:

Management operation services
 M-CREATE – Create an instance of a managed object
 M-DELETE – Delete an instance of a managed object
 M-GET – Request managed object attributes (for one object or a set of objects)
 M-CANCEL-GET – Cancel an outstanding GET request
 M-SET – Set managed object attributes
 M-ACTION – Request an action to be performed on a managed object

Management notification services
 M-EVENT-REPORT – Send events occurring on managed objects

Management association services
To transfer management information between open systems using CMIS/CMIP, peer connections, i.e., associations, must be established. This requires the establishment of an Application layer association, a Session layer connection, a Transport layer connection, and, depending on supporting communications technology, Network layer and Link layer connections.

CMIS initially defined management association services but it was later decided these services could be provided by ACSE and these services were removed. Below is a list of these services which were subsequently removed from ISO 9595:

 M-INITIALIZE – Creates an association with (i.e. connects to) another CMISE
 M-TERMINATE – Terminates an established connection
 M-ABORT – Terminates the association in the case of an abnormal connection termination

See also
Common Management Information Protocol (CMIP)

References

Network management
Management cybernetics
Communications center. In telecommunications, the term communications center has the following meanings: 

 An agency charged with the responsibility for handling and controlling communications traffic. The center normally includes a message center, and transmitting and receiving facilities.
 A facility that (a) serves as a node for a communications network, (b) is equipped for technical control and maintenance of the circuits originating, transiting, or terminating at the node, (c) may contain message-center facilities, and (d) may serve as a gateway.  Synonym comm center.

See also
Network operations center

References

Telecommunications buildings