HOW THE COMPANION MICS SYSTEM WORKS
The Companion Mics system establishes a direct communication
line between the Talkers’ microphones and the Listener’s receiver, which
bypasses the noise and reverberation of the local acoustic environment.
The wireless technology used in the Companion Mics system is similar
to that used by digital cordless phones and other digital users of the
2.4 GHz band.
Rather than using a single frequency, where a competing signal might
interfere, a frequency-hopping technique is used. By jumping quickly from
frequency to frequency in a pseudo-random manner among 79 frequen-
cies, the chance of interference from microwave ovens, other Companion
Mics systems or other users of 2.4 GHz is minimized, so that 10 or more
sets can operate with little audible interference even if they are all in the
same room. When the units are first turned on, the Listener Unit starts its
repeating sequence of frequency hops while each Talker Unit waits, tuned
to one or another of those frequencies, until it receives a transmission
containing the identification code from the Listener Unit. The units then
lock together, jumping from frequency to frequency. This process is
repeated until all Talker Units lock on. Once all units are in communication
with each other, the LED lights stop blinking and the Talkers are heard by
the Listener. From then on, each Talker Unit is in constant communication
with the Listener Unit. The “lock up” sequence normally takes less than
8 seconds, but—rarely—may take 20-30 seconds if heavy interference
is present. A master volume control on the Listener Unit adjusts micro-
phone gain on all units simultaneously. Each individual Talker Unit has an
independent volume control to fine tune an individual microphone gain to
accommodate loud or soft talkers.
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