USB TTL cable no longer working

[taros]

Thanks for the replies.

I use Ubuntu and the appropriate devices are autocreated in /dev/. The default is /dev/ttyUSB0.
I tried two different UART cables, both with the following characteristics,

Code:

[46297.049241] usb 1-9: new full-speed USB device number 4 using xhci_hcd
[46297.178108] usb 1-9: New USB device found, idVendor=067b, idProduct=2303
[46297.178116] usb 1-9: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[46297.178121] usb 1-9: Product: USB-Serial Controller
[46297.178124] usb 1-9: Manufacturer: Prolific Technology Inc.
[46298.217991] usbcore: registered new interface driver usbserial
[46298.218005] usbcore: registered new interface driver usbserial_generic
[46298.218015] usbserial: USB Serial support registered for generic
[46298.219383] usbcore: registered new interface driver pl2303
[46298.219397] usbserial: USB Serial support registered for pl2303
[46298.219411] pl2303 1-9:1.0: pl2303 converter detected
[46298.220266] usb 1-9: pl2303 converter now attached to ttyUSB0

I tried both the PINs 6/8/10 (GND, TX, RX) on the Euler connector and also PINs 6/7/8 (GND, TX, RX) on the Exp connector. 
I did not get any response at speed 115200.
I cannot figure out what changed so that now I do not get any output from the serial cable.
If a solution is found, I will document the whole process on the wiki!