JPS57178456A - Key telephone set - Google Patents

Key telephone set

Info

Publication number
JPS57178456A
JPS57178456A JP6307881A JP6307881A JPS57178456A JP S57178456 A JPS57178456 A JP S57178456A JP 6307881 A JP6307881 A JP 6307881A JP 6307881 A JP6307881 A JP 6307881A JP S57178456 A JPS57178456 A JP S57178456A
Authority
JP
Japan
Prior art keywords
power failure
circuit
office
connection
telephone set
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP6307881A
Other languages
Japanese (ja)
Inventor
Chuta Aikawa
Kiyoshi Shikayama
Junzo Kikuchi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tamura Electric Works Ltd
Original Assignee
Tamura Electric Works Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tamura Electric Works Ltd filed Critical Tamura Electric Works Ltd
Priority to JP6307881A priority Critical patent/JPS57178456A/en
Publication of JPS57178456A publication Critical patent/JPS57178456A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M9/00—Arrangements for interconnection not involving centralised switching
    • H04M9/002—Arrangements for interconnection not involving centralised switching with subscriber controlled access to a line, i.e. key telephone systems
    • H04M9/005—Arrangements for interconnection not involving centralised switching with subscriber controlled access to a line, i.e. key telephone systems with subscriber controlled access to an exchange line

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Sub-Exchange Stations And Push- Button Telephones (AREA)

Abstract

PURPOSE:To maintain a call even if a power failure occurs during the call to an office circuit, by enabling office circuits from respective telephone sets to be used freely without reference to the occurrence of the power failure. CONSTITUTION:A main device is provided with a power failure detecting circuit PSD which detects a power failure, and a control unit which operates all connection relays 1A-8A for office circuit connection according to the detection output of said detecting circuit and also resets connection relays 1C-8C for extension circuit connection. Then, a telephone set is provided with a control part CT which takes a countermeasure to a power failure according to instructions from the control unit when a power failure occurs.
JP6307881A 1981-04-24 1981-04-24 Key telephone set Pending JPS57178456A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6307881A JPS57178456A (en) 1981-04-24 1981-04-24 Key telephone set

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6307881A JPS57178456A (en) 1981-04-24 1981-04-24 Key telephone set

Publications (1)

Publication Number Publication Date
JPS57178456A true JPS57178456A (en) 1982-11-02

Family

ID=13218933

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6307881A Pending JPS57178456A (en) 1981-04-24 1981-04-24 Key telephone set

Country Status (1)

Country Link
JP (1) JPS57178456A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62127187U (en) * 1986-01-31 1987-08-12

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62127187U (en) * 1986-01-31 1987-08-12
JPH0342790Y2 (en) * 1986-01-31 1991-09-06

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