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22
The Basics
DCS (DC) mode
DCS mode sets the scanner to receive transmissions
using frequency modulation (FM) with Digital Coded
Squelch (DCS) subaudible data signaling. DCS is
very similar to CTCSS, except that a digital code is
transmitted instead of an audio tone. Like CTCSS, DCS
allows multiple users to share a single radio frequency
without hearing each other’s transmissions. DCS mode
also features a Code Search setting that allows you
to instantly display and store unknown codes into the
channel memory. DCS data can sometimes be heard
as a low “purring” sound in the background of a voice
transmission. Some DCS systems transmit a special
“turn off code” at the end of each transmission. The
turn off code causes a properly equipped receiver to
mute before the transmission ends, eliminating the
“squelch tail” burst of noise the commonly occurs
when the signal is lost.
Motorola mode
You can set your scanner so it decodes the talk group
IDs used with Motorola trunking systems. This setting
is called the Motorola mode.
Motorola systems are trunking systems used primarily
by business and public safety groups to effi ciently
allocate a small number of frequencies (as few as
fi ve) to many groups of users (as many as several
thousand). To do this, each group of users in the
system is assigned to a specifi c talk group. For
example, the east side patrol offi cers might all be
assigned to talk group 2160. One channel in the system
is continuously transmitting data that identifi es which
talk groups are active on which channel. In addition,