The minimum value of the wanted-to-unwanted signal ratio, usually expressed in decibels, at the receiver input determined under specified conditions such that a specified reception quality of the wanted signal is achieved at the receiver output. [NTIA] [RR]

One of a hierarchy of privileged modes of an information system (IS) that gives certain access rights to user programs and processes that are authorized to operate in a given mode. [INFOSEC-99]

A feature of a transmission entity that enables data on a failed facility to be moved to an alternate facility. This feature may be either revertive or nonrevertive. [T1.231-1997]

Those portions of the TCB whose normal function is to deal with the control of access between subjects and objects [TCSEC].

[In INFOSEC,] packaging techniques for COMSEC material that discourage penetration, reveal a penetration has occurred or was attempted, or inhibit viewing or copying of keying material prior to the time it is exposed for use. [INFOSEC-99]

Special tamper-evident features and materials employed for the purpose of detecting tampering and deterring attempts to compromise, modify, penetrate, extract, or substitute information processing equipment and keying material. [INFOSEC-99]

In telecommunications systems, a device used to protect facilities and equipment from abnormally high voltages or currents.
Note 1: A protector may contain arresters.
Note 2: Protectors may be designed to operate on short-duration phenomena, or long-duration phenomena. The duration should be specified.

1. A formal set of conventions governing the format and control of interaction among communicating functional units.
Note: Protocols may govern portions of a network, types of service, or administrative procedures. For example, a data link protocol is the specification of methods whereby data communications over a data link are performed in terms of the particular transmission mode, control procedures,… (Read More →)

In ISDN, a protocol event (a protocol error or other event) that indicates that a potential trouble condition exists on the ISDN interface.
Note: Examples of events that are not protocol errors that may indicate potential trouble conditions are (a) the transmission of a DM (disconnect mode) in response to a SABME (set asynchronous balanced mode extended) command, and (b)… (Read More →)

A functional unit that uses a specified algorithm to translate a bit stream from one protocol to another, for interoperation.