Connection
Connect rear USB 1 (USB Type-B) to the PC with a data cable. USB 1 carries CI-V and TX/RX audio; no separate audio interface is needed. USB 2 is for I/Q output, not this audio connection. Install the official driver and select the USB 1 CI-V COM.
Radio settings · AFSK
MENU → SET → Connectors. TX: MOD Input; RX: USB AF/IF Output. DATA1 MOD, DATA2 MOD and DATA3 MOD are separate input settings. USB input means connector audio, not USB sideband.
| Item | Setting / check |
|---|---|
| Mode | Start with LSB-D: SSB Data, not the radio’s native RTTY mode. |
| MOD Input → 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. |
| MOD Input → USB MOD Level | Keep the working FT8 value first. Factory default: 50%. Adjust with PSRTTY TX volume. |
| USB AF/IF Output → Output Select | AF: sends received audio to the PC. |
| USB AF/IF Output → AF SQL | OFF (OPEN): prevents radio squelch from cutting PC audio. |
| USB AF/IF Output → AF Output Level | Keep the working FT8 value and check PSRTTY RX level. |
| CI-V → CI-V Address | Default 98h. Match PSRTTY to the radio’s actual CI-V address. |
| USB 1 / USB 2 | Select the USB 1 CI-V COM. The physical USB 2 port is for I/Q output, not a substitute for CI-V/audio connection. |
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.
Connect the radio to the PC with one USB cable to use FSK. See FSK keying output for the radio settings.
Radio settings
| Radio item / connection | Setting / matching |
|---|---|
| USB Keying (RTTY) | USB1 (A) DTR / USB1 (B) DTR |
| USB Keying (CW) | OFF |
| USB SEND | OFF |
| Operating mode | RTTY / RTTY-R |
| RTTY shift | 170 Hz |
| RTTY Mark frequency | 2125 Hz |
For radios with A/B ports
| Shared CI-V port | USB Keying (RTTY) |
|---|---|
| A | USB1 (A) DTR |
| B | USB1 (B) DTR |
A/B identifies a port; DTR/RTS identifies its line. When sharing CI-V, select the same A/B side for USB Keying (RTTY). CI-V on B depends on the model/port-function setting. The original IC-7300 has no A/B choice: select DTR/RTS only.
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-7610)
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-7610 and CI-V CAT PTT. Explicitly select its USB CI-V COM and the same IC-7610 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-7610 documentation. Menu names/positions may vary with firmware or language.