CDAA
Initialism of circularly disposed antenna array.
Electrical engineering
450 entries in this trade.
CDDA
Initialism of circularly disposed dipole array.
CDMA
Initialism of Code Division Multiple Access.
CDR
Initialism of current divider rule or current division rule.
charged particle
Any particle, especially a subatomic particle, that carries an electric charge.
circuit diagram
A schematic representation of electrical connections.
clean feed
The setup of a mixing console or matrix mixer such that the output contains everything except a designated input; often used to prevent echoes or feedback.
clearing
A sequence of events used to disconnect a call, and return to the ready state.
CLEC
Initialism of competitive local exchange carrier.
CLI
Initialism of calling line identity or caller line identity.
clock out
To transmit individual bits of data under the control of a clock.
CLR
Initialism of current-limiting resistor.
CLV
Initialism of constant linear velocity, a qualifier for the rated speed of an optical drive.
CNA
Initialism of cloud native architecture.
COCOT
Initialism of Customer-Owned Coin-Operated Telephone.
combinational logic
A form of digital circuit logic where the current outputs are entirely a function of the current inputs, without having a memory of previous inputs or states.
common carrier
A company providing public telecommunications facilities.
communications satellite
An artificial satellite that relays and amplifies radio telecommunication signals by means of a transponder.
compatibility
the capability of two or more items or components of equipment or material to exist or function in the same system or environment without mutual interference.
conducted interference
Interference resulting from noise or unwanted signals entering a device by conductive coupling, i.e., by direct coupling.
connect up
To join to a network or supply.
constructive interference
When two or more waves overlap, and their crests or troughs align, adding together to create a single, larger wave with a greater amplitude (intensity and height) than the original waves.
CORDIC
Acronym of coordinate rotation digital computer.
corona discharge
The ionization of air (or any other fluid) surrounding an electrically energized conductor, as a result of a strong electric field.
CPC
Initialism of circuit protective conductor.
CPE
Abbreviation of customer-premises equipment.
CQI
Initialism of channel quality indicator.
crimp
To fasten by bending metal so that it squeezes around the parts to be fastened.
cross-bonding
A method to connect power cable by crossing the return conductors between phases to increase cable current rating and reduce electrical losses on the cable sheath.
crossbar switch
A matrix of switches with multiple input and output lines that form a crossed pattern between which a connection may be established by closing a switch located at each intersection.
crossed line
situation when portions of a second call are audible to persons on a telephone connection.
CSP
Initialism of communications service provider (“telecommunications company or telco”).
CTI
Initialism of Computer Telephony Integration.
Curie temperature
The temperature at which the magnetism of a substance changes, specifically when a ferromagnetic material becomes paramagnetic.
cutover
The process of quickly replacing a telephone switchboard, in which the connections are duplicated to the new machine and the original connections are then suddenly disconnected.
CVBS
Initialism of composite video, blanking and sync.
D2M
Initialism of direct-to-mobile (direct-to-smartphone); a technology, or a link using one of the technologies.
daisy chain
A thing resembling a daisy chain (noun sense 1) in having several elements connected together, often in a circle.
Darlington pair
A pair of transistors with the emitter of one connected to the base of the other and the collectors connected together, acting as a transistor with greater amplification.
DAT
Digital Audio Tape, a digital data storage tape format using a dual-spooled cartridge and magnetic tape, used for digital audio and data storage.
data rate
The fee that a cell phone customer is charged for data traffic (sending and receiving data).
data set
A modem that connects a device such as a teletype to an ordinary telephone.
dawn chorus
Radio interference sometimes experienced at sunrise.
day letter
A telegram sent during the day for slightly deferred delivery on the same day, cheaper than a fast telegram, typically with a minimum charge for 50 words or less.
DCH
Initialism of dedicated channel (in UMTS).
DCIM
Abbreviation of digital camera image(s).
DCRS
Initialism of dipole coil resonance system.
DDD
Initialism of direct distance dialing (“network-provided service that enables non-local telephone calls to be made without operator assistance”).
de-emphasis
A signal distortion, carried out at a receiver, in order to undo the effects of pre-emphasis at the transmitter.
dead zone
A region where mobile phones do not operate because there is no base station or repeater nearby.
decade counter
A counter that counts in decimal digits, rather than in binary.
DECT
Initialism of Digital Enhanced Cordless Telecommunications (a standard originated in Europe that is primarily used for creating cordless phone systems).
demarc extension
The transmission path originating from the interface of the access provider's side of a telecommunications circuit Demarcation Point within a premise and ending at the termination point prior to the interface of the edge Customer Premises Equipment. This may include in-segment equipment, media converters and patch cords as required to complete the circuit's transmission path to the edge CPE.
demon dialing
The use of a computer to dial a number repeatedly (usually to a crowded modem pool) in an attempt to gain access immediately after another user has hung up.
detection
The act or process of finding or detecting an electrical signal in a carrier wave.
dial-around
A service that allows an international (or other) telephone call to be made indirectly through another number, thus avoiding the usual call routing and potentially saving money.
difference gate
A logic gate whose output is TRUE when the two inputs are different; a Boolean logic XOR gate.
digital footprint
Digital evidence of a person's activities and interactions with others on the Internet, TV, mobile devices, etc.
displacement current
The direction and rate of change of the electric displacement field at a given point of space and time. It can be expressed as a vector.
double talk
A situation when two people talk at the same time, causing overlapping audio signals.