A core for an electrical conductor. The system may include at least one reference station that has known position coordinates and that is operable to receive first position signals from the positioning system. The guide groove and the guide wall are for guiding a user to insert a plug into the jack without mistake. In a second mode, the system generates virtual characters such as band members, a producer andor a manager to simulate the production and presentation of the recorded tune as a stage show as part of a recording industry. The isochronous cache is reserved for storing the isochronous information, and may be reconfigured into a selectable number of cache channels of varying size that each corresponds to an associated isochronous process. Phases are periodically assigned to shifter patterns within a given range from patterns generated with the phase shift mask, respectively.