JPS56164695A - Key telephone set - Google Patents

Key telephone set

Info

Publication number
JPS56164695A
JPS56164695A JP6870680A JP6870680A JPS56164695A JP S56164695 A JPS56164695 A JP S56164695A JP 6870680 A JP6870680 A JP 6870680A JP 6870680 A JP6870680 A JP 6870680A JP S56164695 A JPS56164695 A JP S56164695A
Authority
JP
Japan
Prior art keywords
circuit
telephone set
key telephone
main device
power supply
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
JP6870680A
Other languages
Japanese (ja)
Inventor
Tatsuya Kato
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.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric Co 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 NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP6870680A priority Critical patent/JPS56164695A/en
Publication of JPS56164695A publication Critical patent/JPS56164695A/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
    • H04M9/003—Transmission of control signals from or to the key telephone set; signalling equipment at key telephone set, e.g. keyboard or display equipment

Landscapes

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

Abstract

PURPOSE:To prevent malfunction due to noise at nonconnection of key telephone set, by providing a current detection circuit stopping the data reception operation of main device, if power supply current is absent between a key telephone set and the main device. CONSTITUTION:Between a main device 1 and a key telephone set 2, 2 pairs of lines 6, 11 are connected, and a power supply 15 connected with a current detecting circuit 16 is connected between a data transmission circuit 3 of the main device 1 and a reception circuit 13 at the center of weight of both the lines 6 and 11, and also, between a data reception circuit 8 and a transmission circuit 9 of the key telephone set 2, a power supply circuit 17 is connected. Further, when the key telephone set 2 is detached from the main device 1, the current detecting circuit 16 detects the disconnection and transmits the detection signal to the circuit 13, which stops the reception of data, allowing to avoid the operation due to noise.
JP6870680A 1980-05-22 1980-05-22 Key telephone set Pending JPS56164695A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6870680A JPS56164695A (en) 1980-05-22 1980-05-22 Key telephone set

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6870680A JPS56164695A (en) 1980-05-22 1980-05-22 Key telephone set

Publications (1)

Publication Number Publication Date
JPS56164695A true JPS56164695A (en) 1981-12-17

Family

ID=13381479

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6870680A Pending JPS56164695A (en) 1980-05-22 1980-05-22 Key telephone set

Country Status (1)

Country Link
JP (1) JPS56164695A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008303012A (en) * 2007-06-06 2008-12-18 Kyocera Mita Corp Image forming device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008303012A (en) * 2007-06-06 2008-12-18 Kyocera Mita Corp Image forming device

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