C4Fm Mode (Digital Mode) Operation - Yaesu FT-991 Operating Manual

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The FT-991 transceiver is capable of using 2, C4FM digital modes: the "V/D mode" which communicates voice and
data simultaneously, and the "Voice FR mode" which transmits digital voice data using the full 12.5 kHz bandwidth.
1. Press the MODE button, and then touch the corre-
sponding key on the LCD to select the C4FM operat-
ing mode. The "C4FM" icon appears in the display.
2. Set the transceiver to the desired operating frequen-
cy.
A :
dvice
The VFO-A frequency can be changed by rotating
the Main Tuning Dial knob or using one of the fol-
lowing methods. For details, see page 42.
 Setting the frequency directly using the number
keys.
 Setting the frequency by rotating the MULTI
knob.
 Setting the frequency using the UP/DWN buttons
on the microphone.
3. Press and hold the
PTT
touch the [ MOX ] on the LCD) to change the trans-
ceiver to transmit mode, then speak into the micro-
phone.
button (or touch the [ MOX ] again
Release the PTT
if you pressed [ MOX ] to enter the transmit mode) to
change the transceiver back to the receive mode.
A :
dvice
 Digital communication mode can be switched be-
tween V/D mode and FR mode (see "Toggling to the
Digital Communication Mode" on page 39).
 The AMS (Automatic Mode Select) function enables
the transceiver to select the appropriate communica-
tion mode according to the received signal. Using
the AMS function, the transceiver recognizes either
analog (FM) or C4FM digital signals and automati-
cally changes to the same communication mode as
the contact station.
n :
ote
 When communicating in V/D mode ("DN" is dis-
played on the LCD), the station location information
is contained within the transmitted digital signal. In
Voice FR mode ("VW" is displayed on the LCD), the
location information is not included in the transmit-
ted signals.
FT-991 O
peraTing
(D
oDe iGital
button on the microphone (or
M
anual
M ) o
oDe peration
MODE Button
Page 95