A self contained breathing apparatus served by a source of breathing gas with a mask and a demand regulator connected to the mask. The magnets are attached to a plate in columns, and adjacent columns have a N-S orientation. The switching control circuit is coupled to output the drive signal in response to the clock signal. An elongated reamer tool has a cannulated central boss for receiving the obturator. The normal vectors are coplanar. Program guide state information is stored in a remote control which generates and delivers a pseudo-interactive guide to end users with the system state information (guide information to channel mapping maintained in the remote control device.