FT-891 | Radio setup guides

Connection

CAT: radio USB → PC, with virtual COM driver. Audio: radio RTTY/DATA (Mini-DIN 6) ↔ audio interface ↔ PC. CAT COM and Audio IN/OUT may belong to different devices. Follow the interface-specific notes below.

Digirig Mobile

PC ↔ Digirig Mobile USB; Digirig AUDIO ↔ FT-891 RTTY/DATA with an FT-891-compatible Mini-DIN 6 audio cable. Also connect radio USB ↔ PC for CAT. Do not use the FT-8xx serial cable on TUN/LIN for CAT.

Digirig DR-891

PC ↔ DR-891 USB-C. Included black cable: AUDIO ↔ RTTY/DATA. Included red cable: DR-891 USB socket ↔ radio USB-B. One PC USB cable, but two paths on the radio: audio and CAT. These differ from Mobile’s green serial cable.

SCU-17

PC ↔ SCU-17 USB; connect its audio I/O to FT-891 RTTY/DATA with a correctly wired cable. SCU-17 audio output → radio DATA IN; radio audio output → SCU-17 audio input. CAT uses radio USB ↔ PC, not the SCU-17 RS-232C cable. Adjust TX/RX knobs.

Radio settings · AFSK

Hold F for menus; select/press MULTI, change value and press again to save. DATA LSB is D-L; DATA USB is D-U. USB here means upper sideband, not audio through a USB connector.

Item	Setting / check
Mode	Use DATA on the LSB side for AFSK, not native RTTY/FSK.
08-01 DATA MODE	OTHERS / OTHER — check AFSK settings rather than PSK-specific settings.
08-09 DATA IN SELECT	REAR: input from rear RTTY/DATA. Choices are MIC/REAR; there is no USB audio choice.
08-12 DATA BFO	LSB: standard PSRTTY LSB-D; verify D-L. Audio input/gain are shared with FT8 D-U. Restore USB side when returning to FT8.
08-10 DATA PTT SELECT	DAKY: this guide uses CAT PTT, not RTS/DTR. Selecting DAKY does not require an external PTT device for CAT operation.
16-14 DATA DATA GAIN	Keep working FT8 gain; adjust with PSRTTY TX volume, starting low while watching power/ALC.
08-11 DATA OUT LEVEL	RX audio level to the interface. Keep the working FT8 value first (default 50); adjust with interface RX gain.
05-06 CAT RATE	Match PSRTTY baud; start with the working FT8 rate.
05-08 CAT RTS	DISABLE/OFF: disable CAT RTS monitoring, a separate setting from RTS PTT.
08-05 DATA LCUT FREQ / 08-07 DATA HCUT FREQ / WDH	Pass both 2085/2295Hz tones. Start with NAR off; check WIDTH and low/high cuts.
08-03 OTHER DISP / 08-04 OTHER SHIFT	Record working FT8 settings; check dial frequency and carrier position. Changes affect both apps.
11-05 SSB MIC SELECT / 16-11 SSB DATA GAIN	Only for plain LSB/USB: 11-05 = REAR, gain via 16-11. DATA D-L/D-U uses 08-09/16-14 instead.

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.

FT-891 controls CAT and FSK through a USB cable connection. Feed receive audio to Audio IN through an audio interface such as SCU-17 or a suitable audio connection.

Radio settings

Radio item / connection	Setting / matching
CAT	FT-891 Enhanced COM
FSK keying output	FT-891 Standard COM, separate from CAT
10-05 RTTY SHIFT PORT	DTR
07-12 PC KEYING	RTS
10-09 RTTY SHIFT FREQ	170 Hz
10-10 RTTY MARK FREQ	2125 Hz
10-11 RTTY BFO	LSB
10-07 RTTY POLARITY-T	NOR (initial example)
PTT (TX/RX switching)	Set PSRTTY PTT to CAT
Operating mode	RTTY
Audio IN	Receive audio from SCU-17 or another interface to Audio IN

Use Enhanced/Standard COM from the FT-891 USB cable connection, not the SCU-17 COM ports. Match 10-05 to PSRTTY DTR/RTS. Frequencies/shift above are standard examples. RX audio needs a separate connection; the radio has no USB audio. Configure radio settings manually.

Keying polarity mapping

PSRTTY inversion	DTR OFF	DTR ON
Not inverted	Mark	Space
Inverted	Space	Mark

The table shows PSRTTY control-signal logic. Match radio POLARITY TX / TX polarity and interface inversion, then verify Mark/Space with the RY test. RX decoding inversion is a separate setting.

Manufacturer reference: manual / USB port settings (FT-891)

If FT8 already works

If FT8 works in D-U, keep cables, audio devices, 08-09 and 16-14. Verify D-L after PSRTTY connects. Changing D-U to D-L does not require a separate audio input setup.

PSRTTY settings · AFSK

Select FT-891, Hamlib and CAT PTT. CAT uses the FT-891 Enhanced COM; Audio IN/OUT uses Digirig or SCU-17 audio devices. Close FT8 and test connection. After automatic LSB-D, verify D-L.

No modulation

CAT TX but no RF: D-L → 08-09 REAR → interface Audio OUT/cable → 16-14, interface TX and PSRTTY volume. Missing RX: interface Audio IN, 08-11 and RX gain.

Official sources

Based on official manufacturer operating/CAT manuals. Names and positions may vary by firmware/region.