Tone Squelch System - Yaesu FT-7100M Operating Manual

O
PERATION

Tone Squelch System

These systems allows silent monitoring until a call directed to you is received, and can offer
listening privacy on an otherwise busy channel.
¦ CTCSS (Continuous Tone Coded Squelch System): This system superimposes a con-
tinuous, subaudible (low-frequency) tone on your transmitted audio. When decoded at
the other station, this allows their squelch to open so as to receive your transmission.
Some "closed" repeaters use this to limit access, or to prevent signals intended for other
repeaters (with the same input frequency) in fringe areas from locking up the repeater.
There are 50 selectable CTCSS tones.
¦ DCS (Digital Code Squelch): DCS operation modulates a subaudible tone according to a
digital protocol (continuous 32-bit synchronous code). DCS is widely used in the com-
mercial land-mobile industry because of its superior performance, and its 104 unique
codes offer greater tone selection than CTCSS.
To use either CTCSS or DCS, both stations must be on the same operating frequency, and
must have selected the same CTCSS tone or DCS code.
Select and activate CTCSS or DCS operation
1. Pressing the [ TONE ] key to select the desired tone control mode from the following:
¦ "ENC" (Encode) appears when the CTCSS tone gen-
erator is activated for transmission only.
¦ "E N C/D E C" (Encode & Decode) appears when the
CTCSS tone squelch is activated for both TX & RX
(only signals "encoded" with the matching tone will
open the squelch; your radio will remain silent other-
wise).
¦ "
" (CTCSS Bell Paging) appears when CTCSS Bell
Paging is activated, as described in detail later.
¦ "DCS " (Digital Code Squelch) appears when Digital
Code Squelch system (TX & RX) is active.
¦ "OFF" (Tone or digital code system is disabled).
2. Within three seconds of releasing the [ TONE ] key, use
the Main Dial knob (or the microphone's [ UP ] / [ DWN ]
buttons) to select the tone frequency (when "E N C ,"
"ENC/DEC," or "
"DCS" is activated).
3. Wait a few seconds: the display will revert to its normal
status, and your new CTCSS or DCS information will be
saved.
26
T
RANSMISSION
" is activated) or DCS code (when
CTCSS Tone Generator
CTCSS Tone Squelch
CTCSS Bell Paging
DSC Code Squelch
FT-7100M Operating Manual