User's Guide

14
Radio Firmware Features
8.2 Scan List
The list of channels that the radio scans and other parameters
associated with scan members are specified in scan list. Each scan
list can be configured in the CPS. Scan List has a collection of groups
and each group consists of User Scan Lists, Dealer Scan List, Priority
Scan Channel and Multiple Group Selection.
9.0 Standard Conventional Operation
Conventional operations of the radio are Carrier Squelch operation,
TPL, DPL and Invert DPL
Different groups of radio users share the same frequency or channel
(community repeater). Without the use of Private Line (PL) tones/
codes, each individual group would constantly listen to the
transmissions of all groups; this is known as Carrier Squelch
operation. Private Line operation is done by outfitting members of
each group with radios containing a unique PL tone/code. Their
radios will then only unmute to transmissions made by other
members of their group. If radios are set to only unmute when a
transmission includes their own PL tone/code, then they are not
disturbed by conversations of other groups. The sub-audible code
that is added to the voice unmutes only those radios with an identical
PL tone/code. There are two forms of PL available: Tone Private Line
(TPL) and Digital Private Line (DPL).
TPL signaling consists of a sub-audible tone that is continuously
modulated onto the carrier. The receiving radio will continuously
monitor the carrier, and if the correct sub-audible tone is present, the
speaker will unmute to the recovered audio. TPL tones are summed
together with the voice information during encoding. There are 39
standard sub-audible Telecommunications Industry Associate (TIA)/
Electronic Industry Association (EIA) tones between 67.0 Hz and
250.3 Hz, inclusively. The radio will follow the standard for sub-
audible Continuous Tone Controlled Squelch System (CTCSS) that is
covered in TIA/EIA-603.
PM1200.book Page 14 Thursday, June 21, 2007 3:58 PM