Instruction manual
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 which 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) with-
out loading or taking appreciable power from that line. Simply stated, as you add more and more sta-
tions 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 (lamp or LED) used to attract the attention of an operator who has removed the headset.
Channel: 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
would be Wireless. . .we make those too. However, if you want privacy and versatility, you probably
want a closed-circuit system or a combination of both.
Cross Talk: Leakage of audio transmissions from one channel to another.
Dry Pair: A telephone term is used to describe a pair of wires (2 conductors) that carry audio but no
DC voltage. Contrast this with a "Wet Pair" that carries both audio and voltage.
Duplex: Duplex refers to bidirectional communications. Normal communication between individual
talking face to face is "full duplex" - in other words you can talk and listen simultaneously. The other al-
ternative is "half-duplex" such as a push-to-talk situation where one station at a time can talk while oth-
ers listen. A walkie-talkie is a good example of half-duplex communication.
IFB: The term means "Interrupted Fold Back." A Fold-Back is a monitor system that allows, for exam-
ple, talent to hear their voices or musicians to hear their voices and instruments on stage. IFB (program
interrupt) disconnects the program audio source while the talk button on the main station is pushed.
ISO: A private conversation path. An ISO channel allows one to simply push a button and transfer
themselves and the person they wish to speak with to an isolated channel.
Linking: Linking ties separate channels into one single party line.
Main Station: This is a product that includes both the ability to communicate with multiple channels
without connecting them together, and to power all the stations connected to these channels.
Master Station: A remote station which needs AC power to operate
Multi-Channel: More than one channel
Party Line (P.L.): Intercom system where all people talking on the system can talk or listen to each
other simultaneously. Also called conferencing.
Point to Point: One path to one person.
Program: Audio source that is fed into the intercom channels.
Clear-Com PS-232 Power Supply
16