I have 2 Kenwood TK-760G-1 radios (eBay special, pulls) that are exhibiting the same symptoms.

First I tried reading them in Linux - I use this system for programming other, unrelated, radios, so it's my go-to, and it failed. (Details below) It says "Radio Ident Successful", then errors out with "The radio send 28 bytes, we need 258". (Which error I could *swear* I've seen here before and will feel really dumb when someone points me to the already discussed fix.)

The radio does go into "PC" mode, per the display.

Puzzled, I then obtained a copy of the Kenwood software, KPG-56D v4.22. Installed, plugged in the cable, found the COM port and...it worked like a champ. More puzzled, I grabbed chirp for Windows, installed, and it worked fine. Able to read and write to the radio

Tried it again in Ubuntu, no joy.

Some details:

jounalctl info when I insert the cable:

Apr 19 21:57:08 xps13 kernel: usb 1-2: new full-speed USB device number 24 using xhci_hcd
Apr 19 21:57:08 xps13 kernel: usb 1-2: New USB device found, idVendor=067b, idProduct=2303, bcdDevice= 3.00
Apr 19 21:57:08 xps13 kernel: usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Apr 19 21:57:08 xps13 kernel: usb 1-2: Product: USB-Serial Controller
Apr 19 21:57:08 xps13 kernel: usb 1-2: Manufacturer: Prolific Technology Inc.
Apr 19 21:57:08 xps13 kernel: pl2303 1-2:1.0: pl2303 converter detected
Apr 19 21:57:08 xps13 kernel: usb 1-2: pl2303 converter now attached to ttyUSB0
Apr 19 21:57:08 xps13 mtp-probe[263657]: checking bus 1, device 24: "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-2"
Apr 19 21:57:08 xps13 mtp-probe[263657]: bus: 1, device: 24 was not an MTP device
Apr 19 21:57:08 xps13 snapd[36670]: hotplug.go:199: hotplug device add event ignored, enable experimental.hotplug
Apr 19 21:57:08 xps13 mtp-probe[263670]: checking bus 1, device 24: "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-2"
Apr 19 21:57:08 xps13 mtp-probe[263670]: bus: 1, device: 24 was not an MTP device
Apr 19 21:57:11 xps13 ModemManager[1008]: <info> Couldn't check support for device '/sys/devices/pci0000:00/0000:00:14.0/usb1/1-2': not supported by any plugin

Permissions on ttyUSB0:

crw-rw---- 1 root dialout 188, 0 Apr 19 21:58 /dev/ttyUSB0

My groups:

4(adm),20(dialout),21(fax),22(voice),24(cdrom),25(floppy),26(tape),27(sudo),29(audio),30(dip),46(plugdev),112(bluetooth),115(tcpdump),120(lpadmin),122(scanner),123(saned),128(pulse),129(pulse-access),131(lxd),132(sambashare),133(wireshark),134(kismet)

Output of a serial sniffer:

pnevulator --ascii --timing-print --tty /dev/ttyUSB0 --read
2021-04-19 21:58:07.523807:
06 .

Output of a different serial sniffer run (when the cable grabbed ttyUSB1):

jpnevulator --ascii --timing-print --tty /dev/ttyUSB1 --read
2021-04-19 21:46:39.400999:
00 .
2021-04-19 21:46:39.560981:
36 30 30 04 FF F1 600...

Occasionally, the serial monitor will show something more, like:

2021-04-19 22:42:00.199228:
00 .
2021-04-19 22:42:12.661137:
06 .
2021-04-19 22:42:13.163410:
76 32 2E 30 30 20 FF FF FF FF 15 57 80 75 C1 42 v2.00 .....W.u.B
90 75 C3 03 00 A1 10 B1 32 EC A0 FD A7 FF 03 7D .u......2......}
B4 D8 02 FD 8D 34 06 FE 55 73 F4 EE 07 73 F5 F0 .....4..Us...s..
07 77 44 16 00 77 E5 75 A0 7E B0 0D 6E 21 B6 FB .wD..w.u.~..n!..
73 F0 EE 07 73 F2 F0 07 77 40 16 00 77 E2 EC A0 s...s...w@..w...
FD A7 FF 03 7D B4 D8 02 FD 8D 34 06 FE 20 C6 01 ....}.....4.. ..
FB 73 F0 EE 07 73 F2 F0 07 77 40 16 00 77 E2 EC .s...s...w@..w..
A0 FD C3 00 04 7D B4 D8 F2 FD 8D 34 06 FD 76 FF .....}.....4..v.
03 7D F2 E7 01 CC 0A 6E 1B 76 0F FA 08 20 6A 14 .}.....n.v... j.
97 DF FA 08 7D E2 03 00 7D E2 E0 97 FD FB 22 04 ....}...}.....".
7D B4 F3 76 0F F0 08 10 6A 05 9F 02 F0 08 F3 76 }..v....j......v
0F 15 09 10 6A 04 F4 5A 05 75 80 80 00 03 7E B0 ....j..Z.u....~.
01 6E 38 76 0F 15 09 08 6A 17 76 0F E5 08 10 6E .n8v....j.v....n
2A D8 02 FD DF E9 03 74 C2 0B FD EE E2 03 FE 1B *......t........
D8 02 FD 11 FE 03 0C 6E 07 D8 02 FD E1 EA 03 74 .......n.......t
C2 0B FD 77 E5 03 97 DF 16 09 76 0F ED 08 02 6E ...w......v....n
2B 76 0F 15 09 08 6A 0E 76 0F 14 09 7F +v....j.v....

If I have the serial monitor running, Chirp instead gives the error "Error reading data from radio", so I don't have much faith that it's actually giving good data.

Using the Kenwood Detect driver returns "No response from radio."

I *can* program the radio in Windows, so this isn't *urgent* but...I don't want to. I'd like to get this working in Linux and also understand what's going on.

Thank you for your time & attention,