Key telephone set

Abstract

Abstract PURPOSE:To prevent a fault of talking due to setting and release left undone by automating 'absence setting' based on the illuminance around each key telephone set. CONSTITUTION:An optical sensor 4 is fitted to the surface of a key telephone set 1 and generates a voltage proportional to the illuminance around a location where the key telephone set 1 is placed. The voltage generated from the optical sensor 4 is converted into a digital data by an A/D converter 5 and inputted to a control circuit section 2. The control circuit 2, based on a digital data from the A/D converter 5, decides whether or not the data value is smaller than the preset value and sends a data of 'absence setting' to a key telephone master set 7 through a data line 6 when smaller. Thus, the setting left undone at seat leaving or the release of absence setting left undone at come back is prevented.

Inventors

• 👤 Tatsu Nakahara
• 👤 Yujiro Nakagawa

Bibliographic Details