Kabushiki Kaisha Toshiba

Setsuo Kimura

Masayuki Tsurusaki

Toshiaki Tanaka

Takashi Watanabe

Hiroshi Mano

Isaku Komuro

Yoshihiro Kawauchi

Nobuhiro Masaki

Terunori Suwa

Yoshihito Nagano

According to this invention, a digital key telephone system connected to an analog public network NW having a function of transmitting a ringing signal including identification information of a calling line through a subscriber line (CO line), accommodating a plurality of extension lines each connected to a digital key telephone (DKT) or a standard telephone (STT) as an extension terminal, and having a function of switching and connecting the subscriber line to the plurality of extension lines or the extension lines to each other includes a called party storage means storing, in advance, information representing the correlation between the calling line and the extension terminals and as a called terminal. When a ringing signal arrives from the analog communication network NW, calling line identification information (caller ID) contained in the ringing signal is detected by a calling line identification information interface unit (RCIU) A control unit (RCTU) determines the called extension terminal on the basis of the detected caller ID and the information stored in the storage means, so the extension terminal receives the call from the digital key telephone interface unit (RDKU) or a standard telephone interface unit (RSTU)

Digital key telephone system and extension terminal device thereof

According to this invention, a digital key telephone system connected to an analog public network NW having a function of transmitting a ringing signal including identification information of a calling line through a subscriber line (CO line), accommodating a plurality of extension lines each connected to a digital key telephone (DKT) or a standard telephone (STT) as an extension terminal, and having a function of switching and connecting the subscriber line to the plurality of extension lines or the extension lines to each other includes a called party storage means storing, in advance, information representing the correlation between the calling line and the extension terminals and as a called terminal. When a ringing signal arrives from the analog communication network NW, calling line identification information (caller ID) contained in the ringing signal is detected by a calling line identification information interface unit (RCIU) . A control unit (RCTU) determines the called extension terminal on the basis of the detected caller ID and the information stored in the storage means, so the extension terminal receives the call from the digital key telephone interface unit (RDKU) or a standard telephone interface unit (RSTU)

According to this invention, a digital key telephone system connected to an analog public network NW having a function of transmitting a ringing signal including identification information of a calling line through a subscriber line (CO line), accommodating a plurality of extension lines each connected to a digital key telephone (DKT),or a standard telephone (STT),as an extension terminal, and having a function of switching and connecting the subscriber line to the plurality of extension lines or the extension lines to each other includes a called party storage means storing, in advance, information representing the correlation between the calling line and the extension terminals,and,as a called terminal. When a ringing signal arrives from the analog communication network NW, calling line identification information (caller ID) contained in the ringing signal is detected by a calling line identification information interface unit (RCIU),. A control unit (RCTU),determines the called extension terminal on the basis of the detected caller ID and the information stored in the storage means, so the extension terminal receives the call from the digital key telephone interface unit (RDKU),or a standard telephone interface unit (RSTU)

Digital button telephone system and extension terminal for the same

A telephone line interface circuit for connecting telephone equipment provided with internal speech lines having predetermined DC impedance to external telephone lines, comprising a rectifying circuit connected with the telephone lines for rectifying the DC voltage coming from the telephone lines; a dial pulse sending circuit which makes connection and disconnection between the output terminals of the rectifying circuit and the internal speech lines for sending dial pulses to the telephone lines; and a polarity inversion detecting circuit which discriminates th evoltage relationship between the telephone lines and the internal speech lines for detecting the polarity inversion of the DC voltage coming from the telephone lines.

Growing community of inventors

Musashimurayama, Japan

Setsuo Kimura