JPS5738049A - Circuit for detecting off-hook of telephone set - Google Patents

Circuit for detecting off-hook of telephone set

Info

Publication number
JPS5738049A
JPS5738049A JP11325480A JP11325480A JPS5738049A JP S5738049 A JPS5738049 A JP S5738049A JP 11325480 A JP11325480 A JP 11325480A JP 11325480 A JP11325480 A JP 11325480A JP S5738049 A JPS5738049 A JP S5738049A
Authority
JP
Japan
Prior art keywords
hook
relay
telephone set
contact
line
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
JP11325480A
Other languages
Japanese (ja)
Inventor
Katsuo Murase
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.)
Ricoh Co Ltd
Original Assignee
Ricoh 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 Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP11325480A priority Critical patent/JPS5738049A/en
Publication of JPS5738049A publication Critical patent/JPS5738049A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/22—Arrangements for supervision, monitoring or testing
    • H04M3/2272—Subscriber line supervision circuits, e.g. call detection circuits

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)

Abstract

PURPOSE:To surely detect off-hook, by providing a switching means between the telephone set connection contact of line selector relay and an off-hook detection relay, even if the tlephone line is connected to any of terminal device side or telephone set side. CONSTITUTION:When a contact 3 of a line changeover relay connected a telephone line and a terminal device, an off-hook detection relay 1 is connected to a DC power supply via S1-M1, S2-M2 of an off-hook detection changeover relay contact 2 and resistors R1, R2, and if a telephone set is at on-hook, the relay 1 is energized and the contact is closed and the on/off of the contact are detected as on-hook/off-hook at the control section. When the telephone line is connected to the telephone set, that is, the contacts are connected as S1-B1, S2-B2, S3-B3, S4-B4, the off-hook can be detected immediately with the relay 1.
JP11325480A 1980-08-18 1980-08-18 Circuit for detecting off-hook of telephone set Pending JPS5738049A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP11325480A JPS5738049A (en) 1980-08-18 1980-08-18 Circuit for detecting off-hook of telephone set

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11325480A JPS5738049A (en) 1980-08-18 1980-08-18 Circuit for detecting off-hook of telephone set

Publications (1)

Publication Number Publication Date
JPS5738049A true JPS5738049A (en) 1982-03-02

Family

ID=14607481

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11325480A Pending JPS5738049A (en) 1980-08-18 1980-08-18 Circuit for detecting off-hook of telephone set

Country Status (1)

Country Link
JP (1) JPS5738049A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59138160A (en) * 1983-01-27 1984-08-08 Canon Inc Facsimile device
JPS62193449A (en) * 1986-02-20 1987-08-25 Fujitsu Ltd Hook-off detecting system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59138160A (en) * 1983-01-27 1984-08-08 Canon Inc Facsimile device
JPS62193449A (en) * 1986-02-20 1987-08-25 Fujitsu Ltd Hook-off detecting system

Similar Documents

Publication Publication Date Title
EP0281147A3 (en) Hold detecting and control circuit for a key telephone system
GB1529452A (en) Detection of direct currents or voltages
JPS5530207A (en) Main station connection system of key telephone system
JPS57168567A (en) Electric power feeding system
JPS5738049A (en) Circuit for detecting off-hook of telephone set
JPS5725758A (en) Message transfer system at night for telephone circuit
JPS6425694A (en) Ac contact defect preventing device
JPS5625867A (en) Information terminal unit with automatic line disconnecting function
JPS53117922A (en) Absence reception voice answer skip system
JPS5444178A (en) Device of detecting abnormality of contact signal transmission circuit
JPS56141648A (en) Automatic answering telephone set
JPS5725787A (en) Control system of channel during service interruption
JPS56119570A (en) Emergency communication system
JPS6484965A (en) Terminal call controller
JPS6413855A (en) Interruption permission type modulating and demodulating device
JPS5720819A (en) Voltage control device of feeding circuit
JPS57152265A (en) Preventing device for holding of telephone circuit by communication equipment
JPS57141147A (en) Radio telephone set
JPS6453676A (en) Terminal calling control device
JPS6469150A (en) Condition checking service
JPS57201366A (en) Remote monitor device
JPS5715566A (en) Automatic part transmitter
EP0324486A3 (en) Circuit arrangement for compensation of the tripping time of an electric current switch
JPS5467649A (en) Automatic power multiplexing device
JPS648767A (en) Facsimile equipment