Search Keyword By: H



A smooth change in the direction of the axis of a waveguide, throughout which the axis remains in a plane parallel to the direction of magnetic H-field (transverse) polarization. Synonym H-plane bend.


In Integrated Services Digital Networks (ISDN), a 384-kb/s, 1472-kb/s, or 1536-kb/s channel, designated as “H0“, “H10“, and “H11“, respectively, accompanied by timing signals used to carry a wide variety of user information. Note: Examples of types of user information representation forms include fast facsimile, video, high-speed data, high-quality audio, packet-switched data, bit streams at rates less than the respective H-channel bit rate that have been rate-adapted or multiplexed together, and packet-switched information.

H-plane bend

Synonym H-bend.


Hierarchical Virtual Private LAN Service


High Availability

HA1-receiver weighting

A noise weighting used in a noise measuring set to measure noise across the HA1-receiver of a 302-type or similar instrument. Note 1: The meter scale readings of an HA1 test set are in dBa (HA1). Note 2: HA1 noise weighting is obsolete for new DOD applications.


1. To break into or use a computer network or use a system without authorization, as a hacker might do. 2. Referring to a track used to bypass a flaw or a bug in an application program or application.


A person who breaks into, or attempts to break into, or use, a computer network or system without authorization , often at random, for personal amusement or gratification, and not necessarily with malicious intent. 2. [An] unauthorized user who attempts to or gains access to an information system (IS). [INFOSEC-99] 3. A technically sophisticated computer expert who intentionally gains unauthorized access to targeted protected resources. [After ANSDIT] 4. Loosely, a computer enthusiast. [ANSDIT] 5. A person who uses a computer resource in a manner for which it is not intended or which is in conflict with the terms of an acceptable-use policy, but (unlike the work of a cracker) is not necessarily malicious in intent.

Hagelbarger code

A convolutional code that enables error bursts to be corrected provided that there are relatively long error-free intervals between the error bursts. Note: In the Hagelbarger code, inserted parity check bits are spread out in time so that an error burst is not likely to affect more than one of the groups in which parity is checked.

half-duplex (HDX) operation

Operation in which communication between two terminals occurs in either direction, but in only one direction at a time. Note: Half-duplex operation may occur on a half-duplex circuit or on a duplex circuit, but it may not occur on a simplex circuit. Synonyms one-way reversible operation, two-way alternate operation.

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