See DIP switch.

The condition that occurs when, in both-way operation, two exchanges attempt to seize the same circuit at approximately the same time. [T1.110-1987] Synonymscall collision, glare[deprecated].

Synonym dual-homed host.

A host computer that participates in two separate networks.
Note: A dual-homed host can provide security functions as a firewall. [2382-pt.35] Synonym dual-homed gateway.

A message that contains two precedence designations.
Note: Usually the higher precedence message is for all action addressees and the lower for all information addressees. [From Weik '89]

In telephone systems, multifrequency signaling in which standard set combinations of two specific voice band frequencies, one from a group of four low frequencies and the other from a group of four higher frequencies, are used. Synonyms multifrequency pulsing, multifrequency signaling.
Note 1: DTMF signals, unlike dial pulses, can pass through the entire connection to the destination user, and therefore… (Read More →)

A user access line normally used for analog voice communication, but which has special conditioning for use as a digital transmission circuit.

1. A duplicate copy made in the same format from one recording medium to another.
2. See audio dubbing.

1. In interfacility cabling, a conduit, which may be direct-earth buried or encased in concrete, used to enclose communications or power cables.
Note: For maximum resistance to rodent attack, direct-earth-buried conduit should have an outside diameter equal to or greater than 6 cm (
2. 25 in. ).
2. See atmospheric duct.

The propagation of radio waves within an atmospheric duct.