Tone Squelch Systems; Coded Squelch System); Dcs (Digital Code Squelch) - Yaesu FT-90R Operating Manual

Operation
These systems allow silently monitoring until a call directed to you is received,
and offer privacy on an otherwise busy channel.
CTCSS (Continuous Tone Coded Squelch System)
This system superimposes a continuous, 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 47 selectable
CTCSS tones.

DCS (Digital Code Squelch)

DCS operation modulates a subaudible tone according to a digital protocol (con-
tinuous 32-bit synchronous code). DCS is widely used in the commercial 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 fre-
quency, and must have selected the same CTCSS tone or DCS code.
To select and activate CTCSS or DCS operation:
Press the [ P1 ] button to select the desired squelch type from the following:
m "E N C " (Encode) appears when the CTCSS tone generator is activated for
transmission only.
m "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 otherwise).
m "B E L L " (CTCSS Bell Paging) appears when CTCSS Bell Paging is acti-
vated, as described in detail later.
m "D C S " (Digital Code Squelch) appears when Digital Code Squelch system
(TX & RX) is active.
m "O F F " (No tone or digital code system activated)
Wait a few seconds; the display will revert to its normal status, and your new
CTCSS or DCS operating mode will be saved.
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Tone Squelch Systems

FT-90R O
PERATING
M
ANUAL