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JPS57185757A - Branching coupling circuit for conference telephone - Google Patents

Branching coupling circuit for conference telephone

Info

Publication number
JPS57185757A
JPS57185757A JP7120281A JP7120281A JPS57185757A JP S57185757 A JPS57185757 A JP S57185757A JP 7120281 A JP7120281 A JP 7120281A JP 7120281 A JP7120281 A JP 7120281A JP S57185757 A JPS57185757 A JP S57185757A
Authority
JP
Japan
Prior art keywords
line
circuit
loss
transmission
amount
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.)
Granted
Application number
JP7120281A
Other languages
Japanese (ja)
Other versions
JPS6155307B2 (en
Inventor
Hitoshi Fuda
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 JP7120281A priority Critical patent/JPS57185757A/en
Publication of JPS57185757A publication Critical patent/JPS57185757A/en
Publication of JPS6155307B2 publication Critical patent/JPS6155307B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/42—Systems providing special services or facilities to subscribers
    • H04M3/56—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Interconnected Communication Systems, Intercoms, And Interphones (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

PURPOSE:To prevent singing or the like, by detecting a level of a transmission signal and setting the loss with the number of each line. CONSTITUTION:A sound energy detection and comparison circuit V receives the energy of transmission of the respective line, detects the line with the maximum energy (considering as the i-th line), takes a transmission variable loss circuit Lsi of the line as 0 dB inserts the amount of loss determined with the output of the circuit V to a reception side variable loss circuit LRi. In the lines other than the i-th line, the amount of loss determined through the result of output of the circuit V is inserted to a transmission side variable loss circuit Ls and the variable loss at the reception side is taken as 0 dB. Further, a connection discriminating circuit K detects the presence/absence of a communication signal inputted to a transmission side input terminal I and the number of connected line actually and the amount of inserted loss to be determined is decided from the result.
JP7120281A 1981-05-11 1981-05-11 Branching coupling circuit for conference telephone Granted JPS57185757A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7120281A JPS57185757A (en) 1981-05-11 1981-05-11 Branching coupling circuit for conference telephone

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7120281A JPS57185757A (en) 1981-05-11 1981-05-11 Branching coupling circuit for conference telephone

Publications (2)

Publication Number Publication Date
JPS57185757A true JPS57185757A (en) 1982-11-16
JPS6155307B2 JPS6155307B2 (en) 1986-11-27

Family

ID=13453845

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7120281A Granted JPS57185757A (en) 1981-05-11 1981-05-11 Branching coupling circuit for conference telephone

Country Status (1)

Country Link
JP (1) JPS57185757A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59153344A (en) * 1983-02-21 1984-09-01 Nec Corp Optical broadcast communication network
JPS59153367A (en) * 1983-02-21 1984-09-01 Hitachi Ltd Level control conference call method
JPS60148263A (en) * 1984-01-12 1985-08-05 Nippon Telegr & Teleph Corp <Ntt> Conference telephone system
JPS62154A (en) * 1985-03-01 1987-01-06 Nec Corp Sound addition distributing device
JPH0332266A (en) * 1989-06-29 1991-02-12 Nec Commun Syst Ltd Conference talking system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0418977U (en) * 1990-06-05 1992-02-18

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59153344A (en) * 1983-02-21 1984-09-01 Nec Corp Optical broadcast communication network
JPS59153367A (en) * 1983-02-21 1984-09-01 Hitachi Ltd Level control conference call method
JPS60148263A (en) * 1984-01-12 1985-08-05 Nippon Telegr & Teleph Corp <Ntt> Conference telephone system
JPS62154A (en) * 1985-03-01 1987-01-06 Nec Corp Sound addition distributing device
JPH0332266A (en) * 1989-06-29 1991-02-12 Nec Commun Syst Ltd Conference talking system

Also Published As

Publication number Publication date
JPS6155307B2 (en) 1986-11-27

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