Filter
Top Products
TRANSCEIVER OPERATION
2-9
November 1999
Part No. 001-7780-500
2.4.4 MONITOR MODE
The monitor mode temporarily disables squelch
control features (such as Call Guard squelch) so that
all messages are heard on the selected channel. It also
overrides the Busy Channel Lockout feature (see next
section) and temporarily halts scanning.
To monitor the selected transmit channel, select
the monitor mode by briefly pressing the Monitor
option switch (if available). The icon is displayed
and the receiver unsquelches (even if no carrier is
detected). To disable the monitor mode and return to
normal operation, press the Monitor switch a second
time.
To monitor the selected receive channel instead of
the transmit channel, press and hold the Monitor
switch until the alert tone sounds (approximately 1
second). This function may be useful, for example,
during weak signal conditions if intermittent
squelching makes a message difficult to understand.
2.4.5 BUSY CHANNEL LOCKOUT
The Busy Channel Lockout feature (also called
Transmit Disable On Busy) automatically disables the
transmitter if the channel is busy when the PTT switch
is pressed. When a busy condition is detected by this
feature, the transmitter is disabled, “BUSY” is indi-
cated in the lower part of the display, and a tone
similar to a standard telephone busy tone sounds until
the PTT switch is released. This feature is
programmed to operate in one of the following modes
on each channel:
Off - The transmitter keys even if the channel is busy.
Noise - The transmitter is disabled if any signal is
detected on the channel.
Tone - The transmitter is disabled if the detected
squelch coding is not correct.
If busy override is permitted by programming, it
is possible to transmit even when the transmitter is
disabled by this feature. Simply quickly release the
PTT switch and press it again.
2.4.6 CALL GUARD SQUELCH
General
Call Guard® squelch (also called CTCSS/DCS
signaling) can be programmed on conventional
channels. This feature eliminates distracting messages
intended for others using the channel by using a
subaudible tone or digital code to control the squelch.
This tone or code is unique to a user or talk group on
that channel. It is transmitted by the mobile placing a
call, and if Call Guard squelch is programmed in the
mobile receiving the call, it must detect the correct
tone or code to receive the call.
Call Guard Squelch Enable/Disable
To disable Call Guard (Selective) squelch so that
all messages on the selected or scanned channels are
heard, press the Normal/Selective option switch if
programmed. The receiver unsquelches only if a
carrier is detected. To re-enable Call Guard squelch,
press the Normal/Selective switch again.
When Call Guard squelch is disabled by this
switch, “SQ NORM” is flashed on the lower line of
the display, and when it is enabled, “SQ SLCT” is
flashed. The selected mode does not change when
other channels are selected or power is cycled. Call
Guard squelch can also be disabled by the monitor
mode described in Section 2.4.4.
Changing the Call Guard Code
If using the full keypad (15-key) model and the
ability to change Call Guard codes has been enabled
by programming, the transmit and receive codes from
one channel can be temporarily or permanently reas-
signed to all channels of the current zone. Proceed as
follows:
1. Using the number keys, enter the number of the
channel that is programmed with the code you want
to reassign to all channels (only channels 1-9 can be
selected). See Section 2.4.2 for information on how
to display channel numbers.
2. The display then briefly indicates “CODE x”, where
“x” is the key that was pressed. The codes assigned