JPS57178455A - Key telephone device - Google Patents

Key telephone device

Info

Publication number
JPS57178455A
JPS57178455A JP6307781A JP6307781A JPS57178455A JP S57178455 A JPS57178455 A JP S57178455A JP 6307781 A JP6307781 A JP 6307781A JP 6307781 A JP6307781 A JP 6307781A JP S57178455 A JPS57178455 A JP S57178455A
Authority
JP
Japan
Prior art keywords
circuit
office
make contact
power failure
relay
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
JP6307781A
Other languages
Japanese (ja)
Inventor
Chuta Aikawa
Noboru Kanzaki
Masateru Kuroda
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 JP6307781A priority Critical patent/JPS57178455A/en
Publication of JPS57178455A publication Critical patent/JPS57178455A/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 hold 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 telephone set is provided with a parallel circuit PF consisting of the relay LS of a low-resistance-value winding which operates by a call current from an office circuit inserted in series to a calling circuit, the make contact of said relay inserted in series to the calling circuit, the make contact of a nonlock type trunk button, and the make contact of a relay released when the power source of a main device is turned off. Further, the main device is provided with connection relays 1A-8A which operate according to the operation of the trunk button, form a connecting circuit for the office circuits, and also hold the operation even in case of a power failure.
JP6307781A 1981-04-24 1981-04-24 Key telephone device Pending JPS57178455A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6307781A JPS57178455A (en) 1981-04-24 1981-04-24 Key telephone device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6307781A JPS57178455A (en) 1981-04-24 1981-04-24 Key telephone device

Publications (1)

Publication Number Publication Date
JPS57178455A true JPS57178455A (en) 1982-11-02

Family

ID=13218907

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6307781A Pending JPS57178455A (en) 1981-04-24 1981-04-24 Key telephone device

Country Status (1)

Country Link
JP (1) JPS57178455A (en)

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