JPS6410763A - Door phone - Google Patents

Abstract

PURPOSE:To enable speaking between a visitor and another telephone set by providing a master unit with a speech path forming means which detects an input of a call button and enables speaking between slave unit and a telephone set corresponding to the telephone number held in a number holding means. CONSTITUTION:The slave unit 5 comprises the call button 9, a voice input means 8 to input a voice, and a voice output means 7 to output a voice signal acoustically. And the master unit is provided with the following: the number holding means 44 to hold prescribed telephone numbers, a number transmission means 47 which detects an input from the call button 9 and outputs a telephone number signal corresponding to the telephone number held in the means 44 to connected public telephone lines L1, L2, and the speech path forming means 56 which connects the voice input means 8 of the slave unit 5 with the voice output means 7 and with the connected public telephone lines L1, L2 to enable speaking with the corresponding telephone set in case this telephone responds to a transmitted telephone number signal from the means 47. As a result, a preliminarily set telephone set is automatically called even if a visitor visits when the user is absent, and direct speaking is enabled between the visitor and the user through public telephone line.