[Plextalk] Pocket USB connection

Hi, When I plug in my USB cable to the port on my Plextalk Pocket it is only making a good connection intermittently. Most of the time I am getting a message saying ' No USB media'. I did try another able at my local computer repair shop but that didn't seem to work at all. Has anyone else experienced the same problem? I am left with the problem of: is it the cable or the port in the Pocket? Thanks, Steve