Communication Definitions
"A" to :Asc",
"Asy" to "Bc",
"Be" to "Bi",
"Bl" to "Cz",
"D" to "E",
"F" to "L",
"M" to "Mod",
"Mu" to "Nu",
"O" to "Z"
Block: A group of bits or digits that is transmitted as a unit and that may be encoded for error-control purposes. A string of records, words, or characters, that for technical or logical purposes are treated as a unit. Blocks (a) are separated by inter-block gaps, (b) are delimited by an end-of-block signal, and (c) may contain one or transmission link. more records. A block is usually subjected to some type of block processing, such as multidimensional parity checking, associated with it. In programming languages, a subdivision of a program that serves to group related statements, delimit routines, specify storage allocation, delineate the applicability of labels, or segment parts of the program for other purposes.
block transfer time: The average value of the duration of a successful block transfer attempt. Note: A block transfer attempt is successful if (a) the transmitted block is delivered to the intended destination user within the maximum allowable performance period and (b) the contents of the delivered block are correct.
Burst transmission: Transmission that combines a very high data signaling rate with very short transmission times. Operation of a data network in which data transmission is interrupted at intervals. Note: Burst transmission enables communications between data terminal equipment (DTEs) and a data network operating at dissimilar data signaling rates. Synonym data burst.
Bus: One or more conductors or optical fibers that serve as a common connection for a group of related devices.
Capacitor: Terms and definitions listed on the Capacitor Dictionary page.
Capacitive coupling: The transfer of energy from one circuit to another by means of the mutual capacitance between the circuits. The coupling may be deliberate or inadvertent. Capacitive coupling favors transfer of the higher frequency components of a signal, whereas inductive coupling favors lower frequency components, and conductive coupling favors neither higher nor lower frequency components.
Carrier Sense Multiple Access (CSMA): A network control scheme in which a node verifies the absence of other traffic before transmitting.
Characteristic impedance (Zo): The impedance of a circuit that, when connected to the output terminals of a uniform transmission line of arbitrary length, causes the line to appear infinitely long. A uniform line terminated in its characteristic impedance will have no standing waves, no reflections from the end, and a constant ratio of voltage to current at a given frequency at every point on the line. Note: If the line is not uniform, the iterative impedance must be used [Maxwell equations].
Codec: Acronym for coder-decoder. An assembly consisting of an encoder and a decoder in one piece of equipment. A circuit that converts analog signals to digital code and vice versa. An electronic device that converts analog signals, such as video and voice signals, into digital form and compresses them to conserve bandwidth on a transmission path. Note: Codecs in this sense are used in this sense for video conferencing systems. Manufacturers of CODEC ICs.
Cyclic Redundancy Check (CRC): An error-detection scheme that (a) uses parity bits generated by polynomial encoding of digital signals, (b) appends those parity bits to the digital signal, and (c) uses decoding algorithms that detect errors in the received digital signal. Note: Error correction, if required, may be accomplished through the use of an automatic repeat-request (ARQ) system. Also reference Definition of Parity Terms.
