An implantable medical device and external base station system are disclosed. The grounded layer has a slot at a position opposed to an end of the signal transmission line. The instruments may be precisely guided by positioning sensors near moveable portions of the instruments. 0 pbw of an amine salt of phosphorus compound andor from 0. An uninterruptable power supply, an AC terminal low voltage distribution, and a DC-DC converter can be installed on the back plane.