Yaesu FT-920 Operating Manual page 17

Interconnection with non-QSK Amplifiers
(Yaesu FL-2100 Series or others)
The T G jack on the rear panel of the transceiver
X ND
provides for Tx/Rx switching of non-QSK amplifiers.
A schematic diagram of the FT-920's internal relay
circuit is shown below.
As the FT-920 is supplied from the factory, the inter-
nal relay is disabled, and a high-dissipation NPN
transistor's (open) collector is connected to the T
G jack. To enable the relay for use with amplifiers
ND
requiring it, move the rear panel T
cated in the hole near the center of the rear panel, to
the R position. Use a thin, insulated object like a
Y
toothpick to move the switch. Then connect the cen-
FT-920 Operating Manual
ter contact of the T
relay control line, using the outer contact of the T
G
ND
and, if compatible, the ALC cable as described in the
QSK amplifier interconnection section above. Refer
to the drawing below for details.
With the relay enabled, the FT-920 can support non-
QSK linear Tx/Rx switching voltages of up to 220 VDC
(maximum permissible DC voltage) at 270 mA, 30
VDC at 2 A, or 125 VAC (maximum permissible AC
voltage) at 500 mA.
Do not exceed the maximum ratings of the
switching circuitry (transistor or relay) of the
FT-920 made available via the B
jacks. Your warranty does not cover damage
caused by improper interconnections to linear
X
amplifiers. When in doubt, it is always safest
to utilize the T
-R switch, lo-
R Y
set to T
the switching requirements of most all com-
monly-available amplifiers.
G RCA jack to the amplifier's
X ND
jack for the shield. Connect the RF coaxial cable
Caution!
G jack with the T
X ND
, as this configuration should handle
R
X
or T G
AND X ND
-R switch
R Y
15