JPS5880937A - Voice switch call device - Google Patents

Voice switch call device

Info

Publication number
JPS5880937A
JPS5880937A JP17879381A JP17879381A JPS5880937A JP S5880937 A JPS5880937 A JP S5880937A JP 17879381 A JP17879381 A JP 17879381A JP 17879381 A JP17879381 A JP 17879381A JP S5880937 A JPS5880937 A JP S5880937A
Authority
JP
Japan
Prior art keywords
circuit
terminal
called subscriber
control circuit
loss
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
JP17879381A
Other languages
Japanese (ja)
Inventor
Hiroshi Kawabe
Masaharu Sato
Mitsuo Sato
Original Assignee
Matsushita Electric Ind 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 Matsushita Electric Ind Co Ltd filed Critical Matsushita Electric Ind Co Ltd
Priority to JP17879381A priority Critical patent/JPS5880937A/en
Publication of JPS5880937A publication Critical patent/JPS5880937A/en
Pending legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04MTELEPHONIC COMMUNICATION
    • H04M9/00Interconnection arrangements not involving centralised switching
    • H04M9/08Two-way loud-speaking telephone systems with means for suppressing echoes or otherwise conditioning for one or other direction of traffic

Abstract

PURPOSE:To prevent breaks of a dial tone and a ringing tone during the calling of a called subscriber, by placing a loss control circuit in a call state on detecting an answer from the called subscriber due to the polarity inversion of a telephone circuit. CONSTITUTION:A voice switch call device has a transmission system 2 and a reception system 6 equipped with variable loss circuits 4 and 8, and a loss control circuit 9 controls the amounts of loss of the circuits 4 and 8 according to the difference in signal level between transmission and reception. A start control circuit 12 is interposed between the hybrid transformer 10 of said device and a telephone circuit 11. Terminals III and IV of the circuit 12 are connected to the circuit 11, and terminalsI and II are connected to the transformer 10. During origination or calling, the terminal IV is held at -48V and the terminal III is grounded; and a relay A is not in operation in said state and a contact 13 is broken to turn off the circuit 9, so that a dial or ringing tone is heard through an amplifier 7 and a speaker 5. When a called subscriber answers, the terminal III is held at -48V and the terminal IV is grounded and then the relay A is energized to make the contact. Consequently, the circuit 9 operates to allow normal mutual telephone service.
JP17879381A 1981-11-06 1981-11-06 Voice switch call device Pending JPS5880937A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP17879381A JPS5880937A (en) 1981-11-06 1981-11-06 Voice switch call device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP17879381A JPS5880937A (en) 1981-11-06 1981-11-06 Voice switch call device

Publications (1)

Publication Number Publication Date
JPS5880937A true JPS5880937A (en) 1983-05-16

Family

ID=16054738

Family Applications (1)

Application Number Title Priority Date Filing Date
JP17879381A Pending JPS5880937A (en) 1981-11-06 1981-11-06 Voice switch call device

Country Status (1)

Country Link
JP (1) JPS5880937A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59206418A (en) * 1983-05-11 1984-11-22 Mitsui Petrochem Ind Ltd Production of 4-methyl-1-pentene polymer
JPS59206415A (en) * 1983-05-11 1984-11-22 Mitsui Petrochem Ind Ltd Polymerization of 1-butene
EP0330384A2 (en) * 1988-02-18 1989-08-30 Nec Corporation Hands-free telephone

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5235907A (en) * 1975-09-16 1977-03-18 Matsushita Electric Ind Co Ltd High sound simultaneous communication unit

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5235907A (en) * 1975-09-16 1977-03-18 Matsushita Electric Ind Co Ltd High sound simultaneous communication unit

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59206418A (en) * 1983-05-11 1984-11-22 Mitsui Petrochem Ind Ltd Production of 4-methyl-1-pentene polymer
JPS59206415A (en) * 1983-05-11 1984-11-22 Mitsui Petrochem Ind Ltd Polymerization of 1-butene
JPH0354687B2 (en) * 1983-05-11 1991-08-21
JPH0354686B2 (en) * 1983-05-11 1991-08-21
EP0330384A2 (en) * 1988-02-18 1989-08-30 Nec Corporation Hands-free telephone

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