This invention relates to novel compounds and hydrochloric acid salts thereof. In the wireless access system, an access point divides terminals into groups such that terminals in one group cannot recognize radio waves sent from terminals in another group, and performs communication with the terminals on a per-group basis. At least one identifying indicium is stored on the EAS device pertaining to the plurality items. The method may further include generating a phase detector output signal indicative of a phase difference between the second phase based on a signal present on the output of the switch.