| 摘要 |
PROBLEM TO BE SOLVED: To perform efficient mutual communication between portable units in the cordless telephone set of a frequency hopping system. SOLUTION: From plural communication channels usable in the frequency hopping system, a base unit 10 selects mutually different start channels for the respective portable units. In order to maintain the communication between the portable unit 20 and the base unit 10 during a frequency hopping cycle, the portable unit 20 and the base unit 10 both generate the set of the communication channels from the selected start channels allocated to the portable unit 20 so as to be used later on a radio frequency link. Also, information for indicating the start channels and security code of the respective portable units 20, 30 and 40 is transmitted from the base unit 10 to the respective portable units 20, 30 and 40 during a registration process by a prescribed communication channel at a radiation energy level sufficiently lower than a level normally used for normal communication. |
