Yaesu FT-920 connexions with Yaesu SCU-17 for AFSK mode / RTTY, WSPR, FT4/FT8, etc.
Pin
1 (AFSK Input): Connect this pin to your TNC’s “AFSK Out” or
“Mic Audio” output line. The optimum input level is 30mV rms, and the input
impedance is 3 k. Your TNC’s audio output level potentiometer will allow you
to set the level to the optimum value. This pin may be used either for 300 baud
SSB-mode digital operation or for 1200-baud FM packet. The bandwidth and
frequency response are not, however, suitable for 9600 baud operation. Be sure
the AFSK-FSK switch on the rear panel is in the AFSK position. For FSK
operation (whereby the TNC closes a line to ground to accomplish teletype
keying), set the AFSK-FSK switch to FSK, and connect your
TNC’s FSK keying line to Pin 1.
Pin
2 (Ground): Connect this to the shield(s) of the cable(s)
used for connections between the TNC and the FT-920.
Pin
3 (PTT): Connect this pin to the PTT line from the TNC.
This pin, when grounded by the TNC, places the FT-920 into the Transmit
condition.
Pin
4 (Audio Out): Connect this pin to your TNC’s “RX Audio”
input line. This is a constant-level (100 mV rms @ 600) audio output line
which is not affected by the position of the front-panel AF GAIN control.
Pin
5 (BUSY): This
is a “Squelch Status” pin not generally required for digital mode operation.
This pin is held at +5V when the squelch is open, and is grounded when the
receiver is muted by the squelch (“nosignal” condition).
As viewed from rear panel (not
from cable!)
Connector view
Data IN – 100 mVrms / 10k Ohms
Data OUT – 100 mVrms / 600 Ohms
FSK OUT – 25 Vcc/50mA/open colector
Data PTT - 25 Vcc/50mA/open colector
|
AFSK
mode
|
|
|
FT-920 pin 1 Data IN (Audio
IN)
|
SCU-17 pin 1 Data OUT (Audio
OUT)
|
|
FT-920 pin 2 GND
|
SCU-17 pin 2 GND
|
|
FT-920 pin 3 PTT
|
SCU-17 pin 3 PTT
|
|
FT-920 pin 4 Data OUT (Audio
OUT)
|
SCU-17 pin 5 Data IN (Audio
IN)
|
|
FT-920 pin 5 Busy
|
SCU-17 pin 6 SQL IN (Busy)
|
|
Menu #
|
Description
|
Available choices
|
AFSK – RTTY
|
AFSK – WSPR
|
AFSK – FT4/FT8
|
|
U-42
|
RTTY Generator Tone Pair
|
Hi 2125U / Lo 1275U / Hi
2125L / Lo 1275L
|
HI 2125L
|
HI 2125
|
HI 2125L
|
|
U-43
|
RTTY Shift
|
170/425/850 Hz
|
170
|
170
|
170
|
|
U-44
|
Shift Polarity
|
Normal /Reverse
|
REV
|
REV
|
REV
|
|
U-45
|
Packet Freq. Display Offset
|
-3.0 ~ + 3.0 kHz
|
2125
|
0000
|
0000
|
|
U-46
|
Packet Subcarrier Frequenc
y
|
1170/1700/2125/2210 USB/LSB
|
2125U
|
2125U / 1700U
|
2125U
|
