The serial console jack is connected to a max3232 (http://pdfserv.maximintegrated.com/en/ds/MAX3222-MAX3241.pdf).
It requires signals over 2V to distinguish 1s from 0s.
My usb adapters generates lower levels and the resulting data is misinterpreted and shown as garbage.
You could check with a multimeter your usb adapter voltage levels. Some adapters allow the selection of 3.3V, 5V as output level.
