omniomni/omni-engineering huggingface dataset:
Communications-electronics. In telecommunications, communications-electronics (C-E) is the specialized field concerned with the use of electronic devices and systems for the acquisition or acceptance, processing, storage, display, analysis, protection, disposition, and transfer of information.

C-E includes the wide range of responsibilities and actions relating to:

 Electronic devices and systems used in the transfer of ideas and perceptions;
 Electronic sensors and sensory systems used in the acquisition of information devoid of semantic influence;
 Electronic devices and systems intended to allow friendly forces to operate in hostile environments and to deny to hostile forces the effective use of electromagnetic resources.

Electronic Communications Equipment 
Communication electronics radio equipment has been a rapidly growing industry for more than a century. Homeland Security in the USA is one of the reasons for the fast growth. Since the invention of the “solid state” transistor in the 1950s and the TTL (transistor-transistor logic) that led to the development of the IC (integrated circuit) in the 1960s the growth in the field of electronics has been phenomenal. As now witnessed in the “radio communications” field. The latest trend is to send conventional LMR (land-mobile-radio) signals over the Internet (Internet Protocol) this is called RoIP (Radio over Internet Protocol), which is just like VoIP (Voice over Internet Protocol) but uses the radio. By sending signals over the Internet it allows radios to be connected together all over the world. Hence: the “Communications Revolution”.

References

Communication circuits
Electronic engineering

it:Ingegneria delle telecomunicazioni
Compatibility. Compatibility may refer to:

Computing
 Backward compatibility, in which newer systems can understand data generated by older ones
 Compatibility card, an expansion card for hardware emulation of another device
 Compatibility layer, components that allow for non-native support of components
 Compatibility mode, software mechanism in which a software emulates an older version of software
 Computer compatibility, of a line of machines
 IBM PC compatible, computers that are generally similar to the original IBM PC, XT, or AT
 Forward compatibility, in which older systems can understand data generated by newer ones
 Hardware compatibility, between different pieces of computer hardware
 License compatibility, of software licenses
 Pin compatibility, in devices that have the same functions assigned to the same particular pins
 Software compatibility, between different pieces of software
 Software incompatibility

Science and mathematics
 Biocompatibility, a description of materials' ability to remain performant in biological tissues
 Blood compatibility, determines what type of donor blood to use in blood transfusions
 Compatibility, a property of splits in phylogenetic trees
 Compatibility (chemical), how stable a substance is when mixed with another substance
 Compatibility (geochemistry), how readily a particular trace element substitutes for a major element within a mineral
 Compatibility (mechanics), the study of compatible deformations in continuum mechanics
 Electromagnetic compatibility, which studies the unintentional generation, propagation, and reception of electromagnetic energy
 Histocompatibility, the degree of similarity of cell surface proteins between individuals
 Genetic compatibility, how well the genes of parents function together in their offspring
 Consistency, logical compatibility between two or more propositions
 Compatible relation, a binary relation that commutes with each operation of an algebraic structure

Other uses
 Astrological compatibility, a branch of astrology that studies relationships by comparing natal horoscopes
 Compatibilism, a philosophical position
 Interpersonal compatibility, the long-term interaction between two or more individuals in terms of the ease and comfort of communication
Component. Component may refer to:

In engineering, science, and technology

Generic systems
System components, an entity with discrete structure, such as an assembly or software module, within a system considered at a particular level of analysis
Lumped element model, a model of spatially distributed systems

Electrical
Component video, a type of analog video information that is transmitted or stored as two or more separate signals
Electronic component, a constituent of an electronic circuit
Symmetrical components, in electrical engineering, analysis of unbalanced three-phase power systems

Mathematics
Color model, a way of describing how colors can be represented, typically as multiple values or color components
Component (group theory), a quasi-simple subnormal sub-group
Connected component (graph theory), a maximal connected subgraph
Connected component (topology), a maximal connected subspace of a topological space
Vector component, result of the decomposition of a vector into various directions

Science
Component (thermodynamics), a chemically independent constituent of a phase of a system

Software
Component (UML), definition of component in the Unified Modeling Language
Component-based software engineering, a field within software engineering dealing with reusable software elements
Software component, a reusable software element

Chinese
Chinese character component, a structural unit between Chinese character strokes and Chinese whole characters.

Other uses
Component (VTA), a light-rail station in San Jose, California
Part of the grammatical structure of a sentence, a concept relating to the catena
Component ingredient, in a culinary dish

See also
Composition (disambiguation)
Decomposition (disambiguation)
Giant component
Identity component
Irreducible component
Spare part
Strongly connected component
Tangential and normal components
:Category:Components
Concentrator. In telecommunications, the term concentrator has the following meanings:

 In data transmission, a functional unit that permits a common path to handle more data sources than there are channels currently available within the path. A concentrator usually provides communication capability between many low-speed, usually asynchronous channels and one or more high-speed, usually synchronous channels. Usually different speeds, codes, and protocols can be accommodated on the low-speed side. The low-speed channels usually operate in contention and require buffering.
 A device that connects a number of links with only one destination, the main function of this device is to make a kind of load balancing between two or more servers connected together, data distribution is done according to the server processing rate.
 A patch panel or other component in the cable plant where cable runs converge.
 ISP used concentrators to enable modem dialing; this kind of concentrator is sometimes called a modem concentrator or a remote access concentrator. The term "access concentrator" is also used to describe similar provider edge equipment used in computer networks that doesn't rely on modems anymore, e.g. FTTH.

Theory
In the evolution of modern telecommunications systems there was a requirement to connect large numbers of low-speed access devices with large telephone company 'central office' switches over common paths. During the first generations of digital networks, analog signals were digitized on line cards attached to the telephone exchange switches. In an effort to reduce local loop costs, it was decided to push this conversion closer to the customer premises by deploying small conversion devices in customer neighborhoods. These devices would combine multiple digital signals on a single link to a larger telephone switch, which would provide service to the customer. These devices were initially called remote concentrators or simply remotes.

In fibre-optic distribution systems which offer triple-play services (voice, television, internet) the digitization has arrived at the customer premises and signals are digitized at the source and combined using customer edge routers. This traffic enters the distribution network at an Optical Network Termination and is carried to the central office using Wavelength division multiplexing and Passive optical networking.

See also

 Ethernet hub
 Oxygen concentrator (Medical application)
 Remote concentrator
 Concentrating solar power (Energy application)

References

Telecommunications equipment

ru:Концентраторы
Connections per circuit hour. In telecommunications, the term connections per circuit hour (CCH) has the following meanings: 
A unit of teletraffic measurement expressed as the number of connections established at a switching point per hour.
A unit of traffic measurement used to express the rate at which circuits are established at a switch.

The magnitude of the CCH is an instantaneous value subject to change as a function of time (i.e. from moment to moment), and is subject to study including load curve and busy hour as other measures of traffic are.

See also
Busy Hour Call Attempts

References

Teletraffic
Cord circuit. In telecommunications, a cord circuit is a switchboard circuit in which a plug-terminated cord is used to establish connections manually between user lines or between trunks and user lines. A number of cord circuits are furnished as part of the switchboard position equipment. The cords may be referred to as front cord and rear cord or trunk cord and station cord. In modern cordless switchboards, the cord-circuit function is switch operated and may be programmable.

In early and middle 20th century telephone exchanges this task was done by a supervisory relay set known variously as junctor circuit or district junctor.  Later designs made it a function of the trunk circuit or absorbed it into software.

See also
Switched loop

References

Telephony equipment
Data access arrangement. The term data access arrangement (DAA) has the following meanings: 
In public switched telephone networks, a single item or group of items at the customer side of the network interface device for data transmission purposes, including all equipment that may affect the characteristics of the interface. 
A data circuit-terminating equipment (DCE) supplied or approved by a common carrier that permits a DCE or data terminal equipment (DTE) to be attached to the common carrier network.

Data access arrangements are an integral part of all modems built for the public telephone network. In view of mixed voice and data access, DAAs are more generally referred to as direct access arrangements.

Requirement for DAAs 
While DAA now describes an integral component of a device that connects to the telephone network, during the 60s and 70s it described a separate device mandated by the Bell System, connected between the telephone line and non-Bell equipment, typically a modem.

Following the Carterfone decision, which required Bell to allow customers to attach any non-harmful equipment to their network, Bell mandated that subscribers use PCAs/DAAs - purchased exclusively from Western Electric - to ensure the network was protected. These devices were not required for Bell-provided equipment, only equipment made by independent manufacturers.

At the time, some subscribers believed that the DAA was a scheme by AT&T to penalize and discourage use of non-Bell modems and recover lost profits from hardware sales, and the FCC began investigations into the legality of the practice. Subscribers also became frustrated when Bell failed to deliver DAAs in a timely fashion after the ruling, leading to the use of unauthorized third-party DAAs.

There were two main varieties of DAA described by AT&T: manual and automatic. A manual DAA required a call to be initiated (or answered) as normal, at which point it could then be connected to the third-party device, while an automatic DAA allowed an attached device to be connected without human intervention, important for receiving modem use.

In 1975, the FCC implemented Part 68 of the FCC Rules, which granted permission for direct connection of any equipment to the telephone network given compliance with specific electrical requirements. This technically eliminated the need for DAAs, although the first modem that didn't require a separate DAA was not marketed until 1977 when a court ruled that Part 68 was legal.

References

External links
 Wireline DAA - introductory slides by 3am Systems
 Direct-Access Arrangements Are Crucial To Successful Embedded-Modem Designs - in-depth article by Jeff Sorensen

Local loop
Data service unit. A data service unit, sometimes called a digital service unit, is a piece of telecommunications circuit terminating equipment that transforms digital data between telephone company lines and local equipment. The device converts bipolar digital signals coming ultimately from a digital circuit and directly from a Channel service unit (CSU), into a format (e.g. RS- 530) compatible with the piece of data terminal equipment (DTE) (e.g. a router) to which the data is sent. The DSU also performs a similar process in reverse for data heading from the DTE toward the circuit. The telecommunications service a DSU supports can be a point-to-point or multipoint operation in a digital data network.

Form and purpose
A DSU is a two or more port device; one port is called the WAN (wide area network) port and the other is called a DTE port. The purpose of the DSU is to transfer serial data synchronously between the WAN port and the DTE ports. If more than one DTE port is used, the DSU assigns the DTE data according to time slots (channels) on the WAN side.

On the WAN side, the DSU, via a CSU, interfaces with a digital carrier such as DS1 or DS3 or a low speed Digital Data Service. On the DTE side, the DSU provides control lines, timing lines and appropriate physical and electrical interface. To maintain the synchronous relationship between the ports, the DSU manages timing by slaving ports to the bit rate of another or to its internal clock. Typically, the DTE port provides timing to the data terminal equipment while the WAN port dictates the rate.

DSUs usually include some maintenance capabilities. At minimum, they can loop data back at either the WAN or DTE ports, or at both. When only one port is looped back, the data received at that port is simultaneously sent back toward the port and passed in normal fashion to the other port. Most DSUs also allow various data patterns to be generated and monitored to measure error rate of the communication link.  A DSU may be a separate piece of equipment, or may be combined in a CSU/DSU.

References

Telecommunications equipment
Data circuit-terminating equipment. A data circuit-terminating equipment (DCE) is a device that sits between the data terminal equipment (DTE) and a data transmission circuit. It is also called data communication(s) equipment and data carrier equipment. Usually, the DTE device is the terminal (or computer), and the DCE is a modem.

In a data station, the DCE performs functions such as signal conversion, coding, and line clocking and may be a part of the DTE or intermediate equipment. Interfacing equipment may be required to couple the DTE into a transmission circuit or channel and from a transmission circuit or channel into the DTE.

Usage
Although the terms are most commonly used with RS-232, several data communication standards define different types of interfaces between a DCE and a DTE. The DCE is a device that communicates with a DTE device in these standards. Standards that use this nomenclature include:
 Federal Standard 1037C, MIL-STD-188
 RS-232
 Certain ITU-T standards in the V series (notably V.24 and V.35)
 Certain ITU-T standards in the X series (notably X.21 and X.25)

A general rule is that DCE devices provide the clock signal (internal clocking) and the DTE device synchronizes on the provided clock (external clocking). D-sub connectors follow another rule for pin assignment. DTE devices usually transmit on pin connector number 2 and receive on pin connector number 3. DCE devices are just the opposite: pin connector number 2 receives and pin connector number 3 transmits the signals.

When two devices, that are both DTE or both DCE, must be connected together without a modem or a similar media translator between them, a crossover cable must be used, e.g. a null modem for RS-232 or an Ethernet crossover cable/body

See also
Networking hardware

References

External links 

 Data Terminating Equipment or Data Circuit-Terminating Equipment speeds, IBM

Data transmission
Telecommunications equipment
Demand assignment. In telecommunications, a demand assignment is a method which several users share access to a communication channel on a real-time basis, i.e., a user needing to communicate with another user on the same network requests the required circuit, uses it, and when the call is finished, the circuit is released, making the circuit available to other users. 

Demand assignment is similar to conventional telephone switching, in which common trunks are provided for many users, on a demand basis, through a limited-size trunk group.

See also
Time-assignment speech interpolation

References

Teletraffic
Demand factor. In telecommunications, electronics and the electrical power industry, the term demand factor is used to refer to the fractional amount of some quantity being used relative to the maximum amount that could be used by the same system. The demand factor is always less than or equal to one. As the amount of demand is a time dependent quantity so is the demand factor.

 

The demand factor is often implicitly averaged over time when the time period of demand is understood by the context.

Electrical engineering 

In electrical engineering the demand factor is taken as a time independent quantity where the numerator is taken as the maximum demand in the specified time period instead of the averaged or instantaneous demand.

 

This is the peak in the load profile divided by the full load of the device.

Example:
If a residence has equipment which could draw 6,000 W when all equipment was drawing a full load, drew a maximum of 3,000 W in a specified time, then the demand factor = 3,000 W / 6,000 W = 0.5

This quantity is relevant when trying to establish the amount of load for which a system should be rated. In the above example, it would be unlikely that the system would be rated to 6,000 W, even though there may be a slight possibility that this amount of power can be drawn. This is closely related to the load factor which is the average load divided by the peak load in a specified time period.

See also 

 Capacity factor
 List of energy storage projects
 Diversity factor
 Utilization factor

References 
 

Power engineering
Demand load. In telecommunications, the term demand load can have the following meanings: 

 In general, the total power required by a facility. The demand load is the sum of the operational load (including any tactical load) and nonoperational demand loads. It is determined by applying the proper demand factor to each of the connected loads and a diversity factor to the sum total. 
 At a communications center, the power required by all automatic switching, synchronous, and terminal equipment (operated simultaneously on-line or in standby), control and keying equipment, plus lighting, ventilation, and air- conditioning equipment required to maintain full continuity of communications.  
 The power required for ventilating equipment, shop lighting, and other support items that may be operated simultaneously with the technical load.  
 The sum of the technical demand and nontechnical demand loads of an operating facility.

References

Telecommunications engineering
Design objective. In communications systems, a design objective (DO) is a desired performance characteristic for communications circuits and equipment that is based on engineering analyses, but (a) is not considered feasible to mandate in a standard, or (b) has not been tested.  

DOs are used because applicable systems standards are not in existence. 

Examples of reasons for designating a performance characteristic as a DO rather than as a standard are (a) it may be bordering on an advancement in the state of the art, (b) the requirement may not have been fully confirmed by measurement or experience with operating circuits, and (c) it may not have been demonstrated that the requirement can be met considering other constraints, such as cost and size. 

A DO is sometimes established in a standard for developmental consideration. A DO may also specify a performance characteristic used in the preparation of specifications for development or procurement of new equipment or systems.

Design is the process of formulation of a plan for satisfaction of human needs

References

Telecommunications engineering
Deterministic routing. In telecommunications, deterministic routing is the advance determination of the routes between given pairs of nodes. Examples:
In a network where routing is controlled by a telephone switch or network switch, switching in which the routes between given pairs of nodes are pre-programmed, i.e., are determined, in advance of transmission. The routes used to complete a given call through a network are identified, in advance of transmission, in routing tables maintained in each switch database. The tables assign the trunks that are to be used to reach each switch code, area code, and International Access Prefix (IAP), usually with one or two alternate routes. 
In a non-switched network, the routes used to send a given message through the network are identified in advance in routing tables maintained in a database.

Notes and references

Telephone exchanges
Telecommunications engineering
Digital milliwatt. In digital telephony, the digital milliwatt is a standard test signal that serves as a reference for analog signal levels in the telecommunications network. When decoding the digital milliwatt, a PCM decoder produces a sinusoidal signal with a frequency of  with one milliwatt in power (, a reference for dBm0).

The digital milliwatt signal is encoded by eight 8-bit words corresponding to one pulse-code modulated cycle of the signal, sampled 8000 times per second. It is typically stored in read-only memory (ROM) in the telecommunication equipment.

The digital milliwatt signal is often generated in instruments in place of separate test equipment. It has the advantage of being tied in frequency and amplitude to the relatively stable digital clock signal and power (voltage) supply, respectively, that are used by the digital channel bank.

References

Telephony signals
Digital multiplex hierarchy. In telecommunications, a digital multiplex hierarchy is a hierarchy consisting of an ordered repetition of tandem digital multiplexers that produce signals of successively higher data rates at each level of the hierarchy.

Digital multiplexing hierarchies may be implemented in many different configurations depending on; (a) the number of channels desired, (b) the signaling system to be used, and (c) the bit rate allowed by the communications media.

Some currently available digital multiplexers have been designated as Dl-, DS-, or M-series, all of which operate at T-carrier rates.

In the design of digital multiplex hierarchies, care must be exercised to ensure interoperability of the multiplexers used in the hierarchy.

Digroup

Digroup is an abbreviation for digital group. In telephony, a basic group in the digital multiplex hierarchy.

In the North American and Japanese T-carrier digital hierarchies, each digroup supports 12 PCM voice channels or their equivalent in other services. The DS1 line rate (2 digroups plus overhead bits) is 1.544 Mbit/s, supporting 24 voice channels or their equivalent in other services.

In the E-carrier European hierarchy, each digroup supports 15 PCM channels or their equivalent in other services. The DS1 line rate (2 digroups plus overhead bits) is 2.048 Mbit/s, supporting 30 voice channels or their equivalent in other services.

See also
Plesiochronous digital hierarchy
Synchronous digital hierarchy

References

Multiplexing