Patent ID: 8639183

Claim:
A communications system comprising: a transponder having no radio wave generating source executes data transmission with a reader/writer, wherein said transponder is incorporated in a memory card having an internal clock and a memory with which said reader/writer reads and writes information, said memory card being used as loaded in a dedicated slot of a host device; said reader/writer transmits a beacon signal telling a service area of said reader/writer at a predetermined time interval; and said memory card waits, during a wait state in which the internal clock is oscillating, for a beacon signal from said reader/writer within a preset period of time after said host device loaded with said memory card is powered on, executes a connection establishment procedure with said reader/writer upon reception of said beacon signal within said preset period of time and, if said beacon signal has not been received within said preset period of time, enters a sleep state in which at least a wait state of said transponder is stopped and the internal clock is stopped and not oscillating.