I seem to be having some trouble getting tapes to load using the 300-baud interface. It would appear that the interface should supply a bit stream to the least-significant bit of the relevant controller port, but I'm not having any success in getting tapes to load, regardless of the polarity that I use.

For reference, I'm using the corrected Grandfather Clock demo from this page: http://www.ballyalley.com/program_downloads/300_baud_programs/Barry_Ellerson/Barry_Ellerson.html