ICOM IC-761 Transceiver Interconnection Diagram with Optional Receive and Transmit Audio Connections.
Female DB-9 Plug (Pin #s Shown)
Optional Mix 73 or Mix 77 Ferrite Bead (8 Places)

CW OUT

3-Conductor 1/4 Phone Plug

Sleeve Ring Tip

To Xcvr Rear Panel Key Jack

CW GND CW Out Shield

See Note 3

To Ham Shack PC COM Port

3-Conductor 1/8" Mini-Phone Plug

FSK IN

To PC Soundcard Line Input (See Note 7)

To FSK/PTT GND

GND Audio Audio

PTT IN

DB9 Connector Shell

IN GND

See Note 4
To PC Soundcard Line Output (See Note 8)
GND Audio Audio To FSK/PTT GND

In Shield

Male 8-Pin DIN Plug (Pin #s Shown)

Audio To IC-761

To Xcvr Rear Panel ACC(1) Jack

Audio From IC-761

FSK OUT

PTT OUT FSK/PTT GND

FSK/PTT Shield FSK/CW Interface Board in Optional Metal Enclosure

See Note 5 See Note 3

DIN Connector Shell
Notes: 1. The connections shown above are based on available documentation but have not been verified. Please review and use your own judgment before making any connections. 2. Make sure the transceiver RTTY settings are set for normal polarity and 170Hz shift. You may set any desirable mark frequency that is available in both the transceiver and MMTTY or other RTTY software you are using. IMPORTANT: Make sure that both your transceiver and RTTY software are set to the same mark frequency. 3. This connection made by mounting the board with metal standoffs or connecting the interface board mounting hole to the metal interface enclosure. You may also ground shields directly to the metal enclosure, if desired. 4. This connection optional. You may float the shield at the interface by leaving it disconnected and insulated from the metal interface board enclosure. 5. If the cable used with the DIN connector is shielded, you may optionally connect the shield to the DIN connector metal shell. This will ground the shield to the transceiver chassis. 6. RTTY and contest software, e.g., N1MM, WRITELOG, etc., must be configured for FSK, not AFSK, RTTY operation. Refer to the software documentation for instructions. 7. For receiving with external RTTY software, e.g. MMTTY, MixW, etc, receive audio must be provided to the line-level input of the PC soundcard. Fixed level receive audio, independent of the AF gain control setting, is available from Pin 5 (AF) and Pin 2 (Ground) of the ACC(1) jack as shown above. This receive audio will support not only RTTY operation, but PSK and other SSB digital modes. 8. Transmit audio for PSK and other SSB digital modes can be provided by connecting the line output of your PC soundcard to Pin 4 (MOD) and Pin 2 (Ground) of the ACC(1) jack, as shown above. Rev A 30 Jan 2011