Telephone terminal device

• US 5,157,711 A
• Filed: 08/28/1990
• Issued: 10/20/1992
• Est. Priority Date: 08/31/1989
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Shimanuki, Masanobu
• Primary Examiner(s): Dwyer, James L.
• Assistant Examiner(s): TSANG, FAN S
• Application Number:
  US07/573,705
• Time in Patent Office: 784 Days
• Field of Search: 379/413, 379/67, 379/88, 379/89, 379/357, 379/211
• US Class Current: 379/88.28
• CPC Class Codes: H04M 1/654 Telephone line monitoring circuits therefor, e.g. ring detectors
• CPC Class Codes: H04M 19/06 in which current supply sources at subordinate switching centres are charged from the main exchange
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A telephone terminal device in connection with an office line, comprises: (a) an office line acquisition unit for acquiring the office line; (b) an office line acquisition controller responsive to a call signal sent through the office line, for driving the office line acquisition unit by call signal power; and a power supply unit responsive to DC power supplied through the office line acquired by the office line acquisition unit, for supplying the supplied DC power to the telephone terminal device as device driving power. The telephone terminal device utilizes DC power supplied from a telephone exchange office through a telephone line so that built-in backup batteries are consumed at the lowest possible consumption rate.

Claims

1. A telephone terminal device having a battery power supply and adapted for connection with an office line, comprising:

(a) battery power checking means, responsive to a call signal sent through said office line, for checking a power supply capability of said battery power supply by using power of said signal;

(b) office line acquisition means for acquiring said office line;

(c) first office line acquisition control means responsive to said call signal, for driving said office line acquisition means by said power of said call signal, when said battery power checking means determines that said power supply capability of said battery power supply is insufficient;

(d) second office line acquisition control means responsive to said call signal, for driving said office line acquisition means by power supplied from said battery power supply, when said battery power checking means determines that said power supply capability of said battery power supply is sufficient; and

(e) power supply means for receiving power supplied through said office line acquired by said office line acquisition means and for supplying received power to said telephone terminal device as device driving power.

2. The telephone terminal device of claim 1, further comprising:

(a) detection means for detecting a drop in power supplied through said office line; and

(b) switching means, responsive to a detection signal from said detection means, for starting to supply power from said battery power supply to said telephone terminal device.

3. A terminal answering device adapted for connection with an office line, comprising:

(a) office line acquisition means responsive to a call signal sent through said office line, for acquiring said office line;

(b) volatile memory means for recording a free outgoing message;

(c) non-volatile memory means for previously storing a fixed outgoing message;

(d) backup power supply means for backing up said volatile memory means;

(e) message playing back means driven after said office line has been acquired, for reading out one message of said free and fixed outgoing messages from one of said volatile and non-volatile memory means to send said one message through said office line;

(f) backup power checking means, for checking a power supply capability of said backup power supply means; and

(g) message control means, responsive to a checked result from said backup power checking means, for controlling said message playing back means to read out said free outgoing message stored in said volatile memory when said checked result indicates a sufficient power supply capability of said backup power supply means, and to read out said fixed outgoing message stored in said non-volatile memory when said checked result indicates an insufficient power supply capability of said backup power supply means.