Allegedly, on or about 29 December 2015, jd1008 sent:
Android is 4.4.2 (nothing newer is available for my phone. Developer option set. usb debugging enabled.
yet, when I plug my phone to usb on laptop, laptop does not mount anything, nor does any icon appear on the panel as a result of plugging in. Also, the phone does not pop up a screen asking me to enable USB in data mode or any other mode.
Recently I've had a few hours playing with an Android tablet (hideous Laser thing). To get it talking with the computer over USB, I had to fiddling around with its USB settings, I can't recall whether it was the general tablet settings, or within its file browser. Go exploring.