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This is different from scanning because you are
searching for frequencies that have not been
programmed into the scanner. When you select
frequency bands to search, the scanner searches for
any active frequency within the lower and upper limits
you specify. When the scanner finds an active
frequency, it stops on that frequency as long as the
transmission lasts. If you think the frequency is
interesting, you can program it into the scanner’s
memory. If not, you can continue to search.
What is CTCSS/DCS?
Your scanner can monitor systems using a Continuous
Tone Coded Squelch System (CTCSS) and Digital
Coded Squelch (DCS) system, which allow squelch to
open only when the tone you have programmed with a
specific frequency is received along with a
transmission.
CTCSS and DCS are subaudible tone signaling
systems sometimes referred to as PL or DPL
(Motorola’s trademarked terms for Private Line and
Digital Private Line respectively). CTCSS and DCS
are used only for FM signals and are usually
associated with both amateur and commercial two-
way frequencies. These systems make use of a
special subaudible tone that accompanies a
transmitted signal.
CTCSS and DCS are used for many purposes. In
many cases, CTCSS and DCS are used to restrict
access to a commercial repeater, so that only those
units which transmit the correct tone along with their
signal can “talk” to the repeater.
CTCSS and DCS are also used in areas that receive
interference where there are several stations with
output frequencies close to each other. When this
occurs, you might hear multiple communications on
the same frequency. The stations might even interfere
UB347ZH.fm Page 16 Thursday, August 31, 2006 11:57 AM
