Connection
Connect rear REMOTE (CI-V) to the PC using a compatible CI-V interface. Connect external sound hardware/radio interface to ACC(1) (8-pin). A USB CI-V cable alone carries no audio. TX: PC output → MOD; RX: AF → PC input.
Radio settings · AFSK
Set MAIN to the operating band/frequency and plain LSB. Disconnect microphone, COMP OFF. This guide uses normal audio through 8-pin ACC(1), not direct 9600 bps input or LSB-D.
| Item | Setting / check |
|---|---|
| Mode | Set MAIN to the operating band/frequency and plain LSB. Disconnect microphone, COMP OFF. This guide uses normal audio through 8-pin ACC(1), not direct 9600 bps input or LSB-D. |
| ACC(1) (8-pin) pin 4 MOD | Interface TX audio → ACC(1) (8-pin) pin 4 MOD. |
| ACC(1) (8-pin) pin 5 AF | ACC(1) (8-pin) pin 5 AF → interface RX input. Normally independent of the AF knob. MAAF SQLM selects MAIN audio/SQL. Use MAIN here. Closed squelch mutes ACC RX audio; open SQL to check. |
| ACC(1) (8-pin) pin 2 GND | Connect pin 2 GND as specified by the audio interface. |
| ACC(1) pin 3 SEND | Compatible PTT interface grounds pin 3 SEND to transmit. A CI-V cable alone cannot operate this PTT line. |
| CI-V Address | Default 42h. Match PSRTTY to the radio’s actual CI-V address. |
| CI-V Baud Rate | Match CI-V Baud Rate and PC speed. |
| Audio TX level | Start with low PC/interface/PSRTTY TX volume. There is no USB MOD Level setting on the radio. |
| Internal → AMOD / PACT | Select AMOD. PACT is for 9600 bps with different input conditions from ordinary AFSK. |
| Internal → MAAF SQLM / SAAF SQLS | MAAF SQLM selects MAIN audio/SQL. Use MAIN here. Closed squelch mutes ACC RX audio; open SQL to check. |
| Internal → MOD input sensitivity | Keep FT8 settings. LOW = 100 mV, HIGH = 2 mV: sensitivity differs greatly. Match interface output. |
FSK keying transmission · Ver1.18
Example: DTR for FSK and CI-V/CAT for PTT. Adjust settings to your wiring and selected signals.
The manufacturer manual specifies AFSK operation for this model. Native direct FSK keying is not supported; use normal AFSK mode.
Manufacturer reference: manual / USB port settings (IC-820H)
If FT8 already works
If FT8 works in plain USB through the same external audio device, keep wiring/gain first, switch the radio to LSB and test RTTY. Do not switch to LSB-D.
PSRTTY settings · AFSK
In PSRTTY 1.16 select external PTT and match the compatible interface COM, RTS/DTR and polarity. CI-V CAT, audio and PTT are separate paths. Automatic mode switching on connection OFF; select plain LSB on the radio. Choose explicit external Audio IN/OUT and the exact radio model.
No modulation
Compare FT8/PSRTTY output devices → check radio mode → TX audio to MOD and RX audio from AF → interface levels. If CAT works but no modulation, check audio cable and Audio OUT first. MAAF SQLM selects MAIN audio/SQL. Use MAIN here. Closed squelch mutes ACC RX audio; open SQL to check.
Official sources
Based on official manuals for each model. Check pin numbers in the rear-view diagram. For generation or regional differences, follow the manual for your radio.