The present invention discloses a method for communicating between communication apparatuses and a communication unit. The new lock modes include a Read, or shared, neighborhood lock mode and a Write neighborhood that enhance concurrency among non-serializable transactions. The method further comprises forming a recess in a source region of the substrate, where the recess has a sidewall, a bottom, and a depth, and where the sidewall of the recess is situated adjacent to a source of the floating gate memory cell. In another embodiment, a method for determining an accurate scanning position for the scanning reflector of the antenna device is disclosed. The interchangeability of the system allows for display of stimulation devices that are particularly configured to stimulate children that are within distinct, defined age groups without requiring replacement of the stimulation system.