OK I think I know the problem.

When I originally called Banner Therapy I asked for the part number for the electrode that takes standard TENS unit wires. When I looked the photo up this morning I don't think they gave me the correct part number. Please call them to see if I am correct. Not sure if an adapter would work since it might pull out during treatment which would not be a good thing since the current must ramp up at the beginning of treatment and then ramp down at the end of treatment.

More later-late for Drs. appt.