Clear-Com PS-704 - Manual (Page 29)

P S - 7 0 4 F o u r - C h a n n e l P o w e r S u p p l y
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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).
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.
IFB: The term means “Interrupt Fold Back.” A fold-back is a monitor system
that allows, for example, talent to hear their voices or musicians to hear their