Kenwood TH-42A - Manual (Page 46)

CONTINUOUS TONE CODED SQUELCH SYSTEM (CTCSS)
The CTCSS feature is available only when a TSU-8
CTCSS unit is installed.
CTCSS functions by using subaudible tones that are
superimposed on a transmitted signal to control a
receiver’s squelch. When used in combination with the
noise squelch, CTCSS provides a simple method to
selectively choose which stations will be heard. This
transceiver offers a total of 38 standardized CTCSS
frequencies.
Monitoring is less tiring when using CTCSS since you
hear only those stations on a particular frequency that
are transmitting the CTCSS tone that you have selected.
SELECTING CTCSS FREQUENCIES
Refer to the chart of frequencies available and the
procedure for selecting the desired frequency on
page 31.
USING CTCSS
To switch ON CTCSS, repeatedly press [T/CT] until
"CT" appears on the display. Each time [T/CT] is
pressed, the display changes as below;
No indicator
t____
^ T CT
No indicator ; Subaudible tone not transmitted and
tone squelch not functional.
T : Subaudible tone transmitted.
CT Subaudible tone-transmitted and tone
squelch functional.
After switching ON the CTCSS function, the squelch will
not open until a signal is received that has the selected
CTCSS Tone superimposed on the signal.
To disable CTCSS, press [T/CT] again.
Note:
"CT" will appear if [T/CT] is pressed when the TSU-8
CTCSS unit is not installed; however, CTCSS will not
function.
When using DTSS or Page with CTCSS, the squelch
opens only if the correct CTCSS tone is received and the
received DTSS or Page code matches the code stored in
your transceiver.
TH-22E/TH-42E:
Selecting the 1750 Hz tone inhibits CTCSS operation. In
addition, selecting 1750 Hz switches CTCSS OFF
automatically if this function is ON at the time.
As soon as
any Tone frequency other than 1750 Hz is selected, the
previous CTCSS status (ON or OFF) is restored.
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