Kenwood TM-255E - Manual (Page 48)

i DUAL TONE SQUELCH SYSTEM (DTSS)
DTSS provides a more refined method than CTCSS
to selectively communicate with specific stations. A
total of 1000 3-digit DTMF (Dual Tone Multi-
Frequency) codes are available to be used as
addresses for stations with which you want to
communicate. These codes can be changed easily
and regularly as required. Due to the quantity of
different codes, large networks can be set up that use
DTSS for selective calling and receiving. By including
group codes in the network plan, sub-groups within
the network can be contacted without disturbing
others monitoring the same frequency.
If your needs are simpler, DTSS also serves a useful
purpose when you only want direct communication
with a few close friends on your favorite frequency. A
good example of this application is at Hamventions
when a particular frequency can be virtually unusable
due to overcrowding. If your group switches ON
DTSS, your squelch only opens when a call is
received encoded with the same code that is stored in
your transceiver. If no signal is received for more
than 2 seconds after DTSS has opened the squelch,
the squelch then closes. Anytime you want to monitor
all activity on the channel, you simply switch OFF
DTSS.
DTSS can only be activated when using FM mode.
STORING DTSS CODES
You can store a DTSS code from 000 to 999 by using
the Tuning control or the microphone, if DTMF audio
from other equipment is picked up by your
microphone while you are entering digits, digits
corresponding to the interfering DTMF audio may be
entered instead of the digits entered on your keypad.
1 Press [F], [REV] to activate Code Select.
2 Turn the Alternate Tuning control to select Menu
No. 00.
• The Code Select display appears with the first
digit of the currently selected code blinking.
Press [SHIFT].
• The next digit in the code starts blinking.
• This step is not necessary if you are using the
DTMF keypad.
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5 Repeat Steps 3 and 4 for the second and third
digits in the code.
6 Press [CLR] or [PTT].
• The previous mode is restored.
ENABLING DTSS
To switch ON DTSS. press [F], [SHIFT].
• "DTSS" appears when DTSS is ON.
• Each press of [F], [SHIFT] switches the
transceiver as follows;
No indicator DTSS ON
("DTSS")
PAGE ON
("PN")
Note:
♦
Both DTSS status and a DTSS code can be stored in a memory
channel; however, only a DTSS status can be stored in the Call
channel. Further, when recalling either a memory channel or
the Call channel with DTSS status ON while using the VFO with
Page switched ON, Page is given priority.
♦
The microphone is inhibited while the DTSS code is
transmitted.
♦
If DTSS and Tone Alert are ON, there is no speaker output
except the alarm tone even if a signal is received with the
correct DTSS code.
Select the first digit for the DTSS code using the
following buttons:
• [F.LOCK] or microphone [UP] ^
Increments digit
• [LOW] or microphone [DWN] ^
Decrements digit
• Alternatively, if your microphone is equipped
with a DTMF keypad, you can enter the DTSS
code by using the keypad numeric keys. Press
the numeric key for the first digit of the code
you want. Jump to Step 5.
DTSS AND REPEATERS
Pressing [PTT] transmits the DTSS signal after a
short delay. This delay helps avoid losing DTSS data
when using repeaters with long response times that
may miss receiving a portion of the DTSS code.
The delay time is 250 ms during simplex operation.
When using a transmit offset or a split frequency, you
can change 350 ms (default) to 550 ms via Menu B,
No. 65 {page 14}.
Note: When a repeater ID and a DTSS code are transmitted at
the same time, DTSS may not function.
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