User's Manual

20-496 Owner’s Manual Draft Page 12/78
occurs when the signal is lost. CTCSS turn off code performance can be affected by weak signals.
DCS Mode (DC)
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. In your PRO-2096 scanner, the DCS feature can be
used to block the reception of transmissions on a shared channel to only those that use the DCS tone that
you have specified. 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/APCO-25 Trunking Mode (MO)
You can set your scanner so it decodes the talkgroup IDs used with Motorola and APCO-25 trunking
systems and follows talkgroup calls in the trunking system. This setting is called the Motorola mode.
Motorola systems are trunking systems used primarily by business and public safety agencies to efficiently
allocate a small number of frequencies (as few as three) to many groups of users (as many as several
thousand). To do this, each group of users in the system is assigned to a specific talkgroup. For example, a
city’s east side patrol officers might all be assigned to talkgroup 2160. One channel in the system is
continuously transmitting data that identifies which talkgroups are active on which channel. In addition, this
talkgroup information is also transmitted as subaudible data on each active channel.
When the scanner receives a transmission on a channel set to the Motorola mode, it first decodes the
talkgroup ID data included with the transmission. In the Open Mode, the scanner stops on the transmission
and displays the talkgroup ID on the bottom line of the display. In the Closed Mode, the scanner only stops
on the transmission if the talkgroup ID matches a talkgroup ID that you have stored in the bank's talkgroup
ID list and have not locked out.
Trunking systems covered by the Motorola mode come in four categories: Type I, Type II, Type I/II Hybrid
and APCO-25. Each category displays and uses talkgroup IDs in slightly different ways.
Motorola Type I IDs are in the form FFF-SS, where;
FFF=Fleet ID
SS=Subfleet ID
Type I systems are usually organized with different user groups assigned to different fleets.