Telephone regulation system and portable telephone terminal device used in such a system

摘要

A telephone terminal includes: a first radio frequency communication unit; a second radio frequency communication unit that communicates through a weak wave; an optical communication unit; a telephony unit; a first switch that selectively couples the first or the second radio frequency communication unit to the telephony unit in response to an externally applied command; a incoming call detecting circuit connected to the first switch; and a second switch that selectively enables communication by the telephony unit through the first radio frequency communication unit or the optical communication unit in response to an incoming call detected by the incoming call detecting circuit, depending on the status of the first switch.