User's Manual

TECHNISONIC INDUSTRIES LIMITED
www.til.ca
TDFM-136A Operating Instructions Page 2-32
TiL 09RE405
Squelch Modes (L1-9, L2-9, L3-9, L4-9)
The radio supports a variety of squelch modes for both analog and digital operation, these are
shown in table 2-8 below.
TABLE 2-9 Receive and Transmit Squelch Modes
Analog Rx Analog Tx Digital Rx Digital Tx
Rx Noise Tx Noise Rg TalkGroup + NAC Tg TalkGroup + NAC
Rt CTCSS Tones Tt CTCSS Tones Rn NAC Only Ti ID Call
Rc DCS Code Tc DCS Code Rm Monitor T- Inhibit
T- Inhibit
Squelch modes are non-orthogonal, that is, they are not the same across differences in Operating
Mode or for receive and transmit operation. While the user might never use certain squelch
modes for certain channels, the associated parameters are always there.
Example: the user may keep a certain channel in analog narrow mode only, with no
selective squelch chosen, but that channel does have a CTCSS tone, a DCS code, a TalkGroup
and a NAC assigned, it is just that these parameters are not used.
Each squelch parameter exists for each channel, and each has a default value, these default
values, like all user editable channel parameters, can be set using the Maintenance Level
command (L4-3).
In addition, Squelch use may be restricted according to: which Squelch Modes may be selected
for any Operating Mode, which Squelch Modes may be edited (e.g. change value), and – in the
case of Tones and Codes – which values are available to be selected. See command L4-9.
Analog Mode 'x' The analog squelch mode 'x' is the default squelch mode, in the case of
the TDFM-136A, the default receive mode is noise squelch. In the case
of transmit, there is no special selective squelch signal added.
Analog Mode 't' The analog squelch mode 't', indicates that both receive and transmit use
CTCSS tone selective squelch. The tones may be the same or different
for receive or transmit.
Analog Mode 'c' The analog squelch mode 'c', indicates that both receive and transmit
use DCS (digitally coded squelch) code selective squelch. The codes
may be the same or different for receive or transmit.
Analog Mode '-' The analog squelch mode '-', is valid for transmit only, and indicates that
transmit is disabled for this memory.
Digital Mode 'm' The digital squelch mode 'm', is valid for receive only, and indicates that
any non-encrypted P25 compliant digital signal, regardless of NAC or
TalkGroup setting, will be received.
Digital Mode 'n' The digital squelch mode 'n', is valid for receive only, and indicates that
any non-encrypted P25 compliant digital signal, having the correct NAC,
will be received.