Cw Key/Keyer Connections - Yaesu FT-857D Operating Manual

The "TX GND" T/R control line is a transistor "open collector" circuit, capable of handling
positive amplifier relay coil voltages of up to +50V DC and current of up to 400 mA. If you
plan on using multiple linear amplifiers for different bands, you must provide external band-
switching of the "TX GND" relay control line from the CAT/LINEAR jack.
Do not exceed the maximum voltage or current ratings for the "TX GND" line at the
CAT/LINEAR jack. This line is not compatible with negative DC voltages, nor AC
voltages of any magnitude.
Most amplifier control relay systems require only low DC voltage/current switching
capability (typically, +12V DC at 25 ~ 75 mA), and the switching transistor in the
FT-897 will easily accommodate such amplifiers.
All commonly-available keyer paddles should work perfectly with the built-in Electronic
Keyer. The wiring configuration for the paddle is shown below.
KEY
GND
For straight-key operation, only the tip and shaft connections are used.
Note: Even when using a straight key, you must use a three-conductor ("stereo") plug. If a
two-conductor plug is used, the key line will be constantly shorted to ground.
When using an external electronic keyer, be absolutely certain that it is configured for "posi-
tive" keying, not "negative" or "grid block" keying. The "key-up" voltage of the FT-857 is
+5V, and the "key-down" current is only about 1 mA.
For CW automated keying using a personal computer, with an external memory keyer pro-
viding for manual sending, it usually is possible to connect the keyed lines together via a
"Y" connector. Check with the documentation accompanying your keyer and your contest/
DX software for any cautions which need to be observed.
FT-857 Operating Manual
L A
INEAR MPLIFIER
Important Note!
CW K /K
EY EYER
KEY GND
I
NSTALLATION
I
NTERFACING
C
ONNECTIONS
DOT
DASH
DOT
DASH
COMMON
COMMON
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