positive logic
The use of the higher voltage level to represent the Boolean value 1 and the lower voltage level to represent the Boolean value 0. For instance: ~5v is equal to logical 1₂, and ~0v is equal to 0₂.
Electrical engineering
651 entries in this trade.
positive-edge-triggered
adjectiveElectrical engineering
Describing a circuit or component that changes its state only when an input signal becomes high.
post office box
A test instrument once used by telephone engineers.
POTS
Acronym of plain old telephone service/system: the old analog landline circuit-switched telephone network
power alley
The line between two subwoofers where both are in phase.
power consumption
The amount of power used multiplied by the amount of time, measured either in kilowatt-hours, horsepower-hours, etc.
power factor
The ratio of the actual power to the apparent power in an alternating current power system; specifically, the cosine of the phase angle between the voltage and the current.
power failure
An unscheduled or accidental break in the supply of electricity.
power to gas
The storing of generated electrical power as a gaseous substance, usually by electrolyzing water into hydrogen and oxygen gases and carbonizing the hydrogen into methane gas.
precursor
adjectiveElectrical engineering
Caused by the following symbol.
prefix
A set of digits placed before a telephone number, to indicate where the number is based, what type of phone number it is (landline, mobile, toll-free, premium rate etc.)
presentity
An entity (usually a human) which provides information about its presence (whether it is available and willing to communicate through communication services).
PRI
Initialism of primary rate interface.
primary rate interface
an ISDN service delivered over T1, E1 or J1 datalines, with delivery of connections between 1472 kilobits per second and 1984 kilobits per second (kibibits)
primary time standard
A time standard that does not require calibration against another time standard.
prime implicant
A group of related 0's (implicant) on a Karnaugh map which is not subsumed by any other implicant (of 0's) in the same map.
private branch exchange
A telecommunications switching system, physically located at a customer's place of business, that provides internal communication between users and also access to outside (trunk) telephone lines.
programmable read-only memory
A type of read-only memory which can be written to once (write once, read many memory/WORM), and thereafter becomes fixed in value.
propagation constant
The change underdone by the amplitude and phase of an electromagnetic wave as it travels in a certain direction.
propagation delay
The time taken for a signal to reach its destination.
proration
In budgeting, the proportional distribution or allocation of parameters, such as noise power and transmission losses, among a number of tandem-connected items, such as equipment, cables, links, or trunks, in order to balance the performance of communications circuits.
proximity effect
A condition when a power cable carrying electric current which is non-uniformly distributed due to the presence of other power cable or conductor nearby. This phenomena increases the apparent resistance of the power cable.
PSDU
physical layer service data unit.
PSNEXT
Initialism of power sum near-end crosstalk.
PSTN
Initialism of public switched telephone network
PTC
Pacific Telecommunications Council.
pulse dialing
A system of telephone dialing in which each digit is transmitted as the equivalent number of pulses.
pulse repetition time
The elapsed time from the beginning of one pulse to the beginning of the next pulse.
push notification
The delivery of information from a software application to a computing device without a specific request from the client.
push time
The time when a remote server sends an unsolicited update.
QoS
Initialism of quality of service.
quality of service
The overall performance of a telephony or computer network, based on error rates, throughput, transmission delay, etc.
quantize
To approximate a continuously varying signal by one whose amplitude can only have a set of discrete values
quarter-phase
adjectiveElectrical engineering
Differing in phase by a quarter of a cycle; two-phase.
radar cross section
A measure of the detectability of an object by radar.
radiant heat
Heat or warmth transferred directly to people and objects in a space via infrared radiation, similar to the sun's warmth, rather than heating the air first via convection.
radio-frequency identification
The storage and retrieval of data using tags attached to individual packages, animals or people; the tags contain an integrated circuit to store and process the data, and an antenna to transmit and receive such data.
random access memory
Computer memory, usually volatile, that stores program and data values during operation and in which each word of memory may be directly (randomly) accessed.
rat-tail splice
A simple method of joining two ends of metal wire by twisting them together.
receive
To detect a signal from a transmitter.
refarming
The abolition of existing band allocations in the radio spectrum and the more efficient reallocation of the spectrum into smaller bands.
REIN
Acronym of repetitive electrical impulse noise.
remote access
A communication with a data processing facility from a remote location or facility through a data link.
reperforator
A device for punching a duplicate perforated paper tape of incoming messages for later retransmission.
repetition time
The amount of time from the application of an excitation pulse to the application of the next pulse.
resistivity
The resistance offered at a particular temperature by an electrical conductor of any given material in a cube of unit length, expressed in ohm-metres (Ωm) in the metric system of measurement.
resonant
adjectiveElectrical engineering
Adjusted as to dimensions so that currents or electric surgings are produced by the passage of electric waves of a given frequency.
response time
The time taken for the display of an instrument to move to a new value following a step change.
retardation
A decrease in the speed of telegraph signalling.
retarded time
The time when the field begins to propagate from the point where it is emitted to an observer.
return current
The electric current in a circuit which flows back to its source, or to earth.
return path
The route by which a current or signal returns to its source, or to earth.
ring cadence
The ringing pattern heard by the dialer before the called party picks up the call.
ring off
To disconnect at the end of a phone call.
ring out
To make a phone call from an internal phone system to a general telephone network number.
ring time
The duration of time from the moment that the respondent's telephone begins ringing until the moment it is answered.
ringback
The sound transmitted back to a caller to indicate that the telephone they are calling is ringing.
ringdown
A signal to a telephone operator that both rings a bell and allows a relay to drop.
ringer equivalence number
A number denoting the electrical load of a telephone ringer circuit on a particular line.
RJ
Initialism of registered jack.