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end of the transmission. If enabled, audible side tones will be heard in the
radio speaker as well. If PTT is pre-programmed as one of the triggers, the
microphone will become active for voice communication after the tone
sequence is complete.
Tone encode will be transmitted with Channel Guard if one is defined, and
tones are always transmitted in clear voice mode, even if the channel is set
for digital or private (see VOICE MODES). Digital or private voice
transmission will resume normally after the tone transmission.
SCANNING CONVENTIONAL CHANNELS
Channels which have been previously added to the scan list on a per system
basis may be scanned. The selected channel is scanned (if enabled through
programming) whether or not it is in the scan list. Each conventional
system's channel scan list is retained in memory when the radio is turned
OFF.
The scan rate will vary depending upon the number of channels in the scan
list and whether or not the radio is programmed to scan for channels with
decoding enabled. Fewer channels will result in a faster scan rate. If
programmed for dual-priority scan operation, the priority-one, priority-two
and the remaining scan list channels are scanned. Once a signal is detected
and the correct encoded squelch signal is decoded (if programmed), the
radio receives the message and displays the received scan channel. At the
same time, scanning continues on the priority-one and priority-two
channels. Should the priority-one or priority-two channel carrier, regardless
of encoded squelch decoding, be detected while a non-priority channel is
being received, the display name is updated and the received channel is
switched to the priority channel. Scanning of the priority-one channel will
continue if a message is being received on the priority-two channel.
While receiving a call on a non-priority or a priority two channel, the radio
periodically checks the priority one and two channels. If Scan with Channel
Guard is enabled, the radio will use Channel Guard to decide whether to
unmute on a priority channel. The radio will stop, on squelch detection, on a
priority channel. In normal operation, the radio will unmute only on
detecting the correct Channel Guard; otherwise, it will remain muted until
the priority channel call and hang time have ended. An optional feature
allows the radio to continue scanning upon the detection of the wrong
Channel Guard on a priority channel. The user can then select the rate this
channel is scanned until the call there ends.