Abstract: A cordless telephone includes a base unit and a handset unit. When the handset unit is mounted on the base unit, an identifying code is automatically generated and stored in both units. Thereafter, when an incoming or outgoing telephone call is initiated, the two stored identifying codes are compared, and the telephone call proceeds only if the two identifying codes are identical. The new identifying code is generated as a counted value in accordance with a predetermined time following the mounting of the handset unit of the base unit. By having the predetermined time vary from telephone to telephone, the identifying codes will also vary, eliminating crosstalk interference and the risk of wiretapping.