Yaesu FT-847 Operating Manual page 31

(8) STBY Jack
This 5-pin mini-DIN connector provides "closure-to-
ground" switching lines for T/R control of external
amplifiers. One connection is provided for HF opera-
tion, and one each for the 50, 144, and 430 MHz bands.
The maximum ratings for these connections are +24V
DC at 100 mA (only positive DC voltages are accept-
able).
(9) SP Jack
This 3.5 mm, 2-pin miniature phone jack provides re-
ceiver audio output for an external speaker. The audio
output impedance is 4 ~ 16 , and the level varies
according to the setting of the front panel's AF (G
control.
(10) EXT PTT Jack
This "RCA" female connector is used for connection
to a footswitch or other external switch for T
mand control of the transceiver. This jack is wired in
parallel with the front panel's MOX switch; shorting
this jack to ground causes the transceiver to be placed
in the Transmit mode, while opening the connection
to this jack returns the transceiver to the Receive mode.
Open-circuit voltage is +5V DC, and closed-circuit
current is 1 mA.
Note: This jack is designed to be used for external
PTT input only. Do not attempt to use the PTT
jack for switching of amplifiers or other exter-
nal devices (use the STBY jack for controlling
such devices).
FT-847 O
PERATING
Rear Panel Connectors
)
AIN
/R com-
X X
M
ANUAL
(11) EXT ALC Jack
This "RCA" female connector may be used to a linear
amplifier's ALC (Automatic Level Control) connec-
tor, to prevent over-drive by the transceiver. The speci-
fied control voltage range is 0V ~ 4V DC, with 4V
corresponding to the maximum degree of power re-
duction being applied to the transceiver.
(12) 144 MHz Coaxial Jack
This Type "M" (SO-239) jack is for connection of your
antenna for the 144 MHz band.
(13) HF Coaxial Jack
This Type "M" (SO-239) jack is for connection of your
antenna for the 1.8 ~ 29.7 MHz bands.
(14) 50 MHz Coaxial Jack
This Type "M" (SO-239) jack is for connection of your
antenna for the 50 MHz band.
(15) 430 MHz Coaxial Jack
This Type "N" jack is for connection of your antenna
for the 430 MHz band. Do not, under any circum-
stances, attempt to connect a Type "M" (PL-259) plug
to this jack!
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