AB-120 Announcer Console
5
Glossary
Some of the terms used when discussing critical communications for television or theatre may
be new to you as they are unique to intercom applications. Although many of the terms are
common to other audio applications, to be certain you understand their meanings we offer the
following definitions:
All Call: Ability to push one button from the main station and talk to all channels at once on a
multiple channel system.
Ambient Noise: Those background sounds that are not part of the specific communication but
are picked up by the microphone. Selection of a good “noise-cancelling” mic will reduce
ambient noise.
Beltpack: A portable electronics package worn on the belt or mounted on a wall or other
convenient location. Interconnects to system with mic cable and is powered by a central power
supply or main station.
Bridging, High Impedance (hi-Z): A method of connecting to an audio line (such as Clear-Com)
without loading or taking appreciable power from that line. Simply stated, as you add more and
more stations to the line, the volume remains constant.
Call Signaling: This feature is included with the majority of Clear-Com products. It is a visual
indicator on a station (red light) used to attract the attention of an operator who has removed
the headset.
Channel vs. Station: A channel is the line that connects parties together within a party line - it
is a two-way talk path. For example, if you have six people who need to hear one director, you
have a seven-station single-channel need. If the same director needs to speak privately to any
one of the six, add a second channel. You now have a seven-station, two-channel system.
Closed-Circuit: Any intercom which is connected via cable (also called hard-wired). The other
type of intercom is wireless and is also available from Clear-Com. However, if you want
privacy and versatility, you probably want a closed-circuit system or a combination of both.
Crosstalk: Leakage of audio transmissions from one channel to another.
Dry Pair: A telephone term is used to describe a pair of wires (two conductors) that carry audio
but no voltage. Contrast this with a wet pair that carries both audio and voltage.
Duplex: Duplex refers to bi-directional communications. Normal communication between
individuals talking face to face is “full duplex”; in other words, you can talk and listen
simultaneously. The other alternative is “half-duplex,” such as a push-to-talk situation where
one station at a time can talk while others listen. A walkie-talkie is a good example of half-
duplex communication.
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