Search Keyword By: X



Unassigned overhead bits. Transmitters should code these bits as zeros while receivers are required to be capable of ignoring the value contained in these bits. [T1.646-1995]

X-dimension of recorded spot

In facsimile systems, the effective recorded spot dimension measured in the direction of the recorded line. Note 1: By “effective recorded spot dimension” is meant the largest center-to-center spacing between recorded spots, which gives minimum peak-to-peak variation of density of the recorded line. Note 2: “X-dimension of recorded spot” implies that the facsimile equipment response to a constant density in the object (original) is a succession of discrete recorded spots.

X-dimension of scanning spot

In facsimile systems, the distance between the centers of adjacent scanning spots measured in the direction of the scanning line on the object. Note: The numerical value of the X-dimension of scanning spot depends upon the type of system.

x-y mount

Synonym altazimuth mount.

X.-series Recommendations

Sets of data telecommunications protocols and interfaces defined by CCITT (now, ITU-T) Recommendations. Note: Some of the more common X.-series Recommendations are:

  • X.25: A Recommendation for public packet switched communications between a network user and the network itself.
  • X.75: A Recommendation for public packet switched communications between network hubs.
  • X.400: An addressing scheme for use with e-mail.
  • X.500: An addressing scheme for directory services.

X.75 Gateway Service

A protocol for network interworking which supports communication between adjacent networks and communication thru transit networks.


Any type of DSL Technology (x=type)

xerographic recording

Recording enabled by the scanning action of an optical beam on a photoconducting surface on which an electrostatically charged latent image is developed with a resinous powder (toner).


Extensible Hypertext Markup Language


Abbreviation for eXtensible Markup Language. A trimmed specification or version of the Standard Generalized Markup Language (SGML) that allows Web developers to create customized tags for additional functionality.

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