Connection
Connect rear USB B (Type-B) to the PC with a data cable. USB carries CI-V and TX/RX audio; no separate audio interface is needed. Front USB A is for a keyboard, USB memory and similar devices. Install the official driver and select the IC-7600 CI-V COM.
Radio settings · AFSK
Audio settings: SET [F-6] → ACC [F-2]. Check USB Audio SQL, USB MOD Level, DATA OFF MOD and DATA1 MOD–DATA3 MOD. CI-V and USB Serial Function: SET → OTHERS [F-5]. USB audio input is separate from USB sideband.
| Item | Setting / check |
|---|---|
| Mode | Start with LSB-D: SSB Data, not the radio’s native RTTY mode. |
| ACC → DATA1 MOD | PSRTTY 1.16 automatic Data-mode switching selects DATA1: check DATA1 MOD = USB. Factory default is ACC. Setting only DATA2 MOD to USB does not supply audio in DATA1. |
| ACC → USB MOD Level | Keep the working FT8 value first. Factory default: 50%. Adjust with PSRTTY TX volume. |
| ACC → USB Audio SQL | OFF (OPEN): prevents radio squelch from cutting PC audio. |
| Audio IN / Windows recording level | The AF knob does not adjust USB RX audio. Check Windows recording level and PSRTTY Audio IN/RX level. |
| OTHERS → CI-V Address | Default 7Ah. Match PSRTTY to the radio’s actual CI-V address. |
| OTHERS → USB Serial Function | Set CI-V. Decode outputs the radio’s decoded text; it is not CAT control. |
FSK keying transmission · Ver1.18
Example: DTR for FSK and CI-V/CAT for PTT. Adjust settings to your wiring and selected signals.
Serial keying for TX; Audio IN for RX. Neither primary nor secondary Audio OUT is used. Check radio RTTY mode, 170 Hz shift and Mark frequency. Keying polarity is independent of RX inversion.
The manufacturer manual uses the ACC RTTY keying input for FSK. A separate serial port and a suitable FSK interface are required. A USB socket does not mean FSK is available with only a USB cable. Never connect RS-232 signals directly to ACC.
Radio settings
| Radio item / connection | Setting / matching |
|---|---|
| FSK input / keying | ACC (1): RTTY / FSK |
| Serial connection | Use a separate FSK COM port from CAT for this model. Check the connection and avoid PTT signal conflicts. |
| Operating mode | RTTY / RTTY-R |
| RTTY shift | 170 Hz |
| RTTY Mark frequency | 2125 Hz |
| PTT (TX/RX switching) | Do not assign the same line to PTT and FSK |
| Audio IN | Use the usual receive audio input |
The manufacturer manual uses the ACC RTTY keying input for FSK. A separate serial port and a suitable FSK interface are required. A USB socket does not mean FSK is available with only a USB cable. Never connect RS-232 signals directly to ACC. With external control set to radio PTT, a dedicated FSK COM can share different lines, for example FSK=DTR and PTT=RTS. Keep this port separate from CAT and never assign both functions to one line.
Keying polarity mapping
| PSRTTY inversion | DTR OFF | DTR ON |
|---|---|---|
| Not inverted | Mark | Space |
| Inverted | Space | Mark |
This table maps PSRTTY control signals. It is independent of A/B selection and RX decoding inversion. Start without inversion, then match the radio/interface polarity.
Manufacturer reference: manual / USB port settings (IC-7600)
If FT8 already works
Even with FT8 in USB-D, check DATA1/2/3. USB-D and LSB-D share input only for the same Data number. FT8 DATA2 may already use USB, but PSRTTY 1.16 auto-switches to DATA1, so DATA1 MOD must be USB. Plain USB uses DATA OFF MOD. Keep the working FT8 USB MOD Level first.
PSRTTY settings · AFSK
Select IC-7600 and CI-V CAT PTT. Explicitly select its USB CI-V COM and the same IC-7600 USB audio device for Audio IN/OUT. Start with LSB-D. Close other apps using that COM.
No modulation
Compare FT8 and PSRTTY output devices → verify LSB-D after connection → check DATA1 MOD = USB → check USB MOD Level and PC/PSRTTY transmit volume. Start with low audio and observe radio power and ALC.
Official sources
Based on official IC-7600 documentation. Menu names/positions may vary with firmware or language.