JPS57210756A - Telephone exchanger - Google Patents

Telephone exchanger

Info

Publication number
JPS57210756A
JPS57210756A JP9509681A JP9509681A JPS57210756A JP S57210756 A JPS57210756 A JP S57210756A JP 9509681 A JP9509681 A JP 9509681A JP 9509681 A JP9509681 A JP 9509681A JP S57210756 A JPS57210756 A JP S57210756A
Authority
JP
Japan
Prior art keywords
subscriber
relay
terminal
broadcast
terminals
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
JP9509681A
Other languages
Japanese (ja)
Inventor
Tsutomu Kunida
Junya Ishizaki
Taro Matsui
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 JP9509681A priority Critical patent/JPS57210756A/en
Publication of JPS57210756A publication Critical patent/JPS57210756A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/65—Arrangements characterised by transmission systems for broadcast
    • H04H20/76—Wired systems
    • H04H20/77—Wired systems using carrier waves
    • H04H20/81—Wired systems using carrier waves combined with telephone network over which the broadcast is continuously available
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements

Abstract

PURPOSE:To realize the detection of hook-off of a telephone set in braodcasting, by applying a DC bias at an input terminal of a broadcast sound applied to a subscriber circuit, in an exchanger providing subscriber circuits between telephone sets and crossbar switches. CONSTITUTION:When a caller hooks up a handset with a broadcast audio signal instructing signal not applied at a terminal 30, a hook switch 22 is closed, a current flows from -24V at a terminal 28 to a relay 70 of a subscriber circuit 4 and contacts 71-74 are contacted, terminals 40 and 41 go to OV, hook-off is informed to a central controller (not shown) of an exchanger and if a called party is not busy, since a relay 60 is operated, a relay 50 is not activated even if the instruction signal is applied to the terminal 30, and no broadcast sound can be listened to the subscriber. If a subscriber 1 is not busy, when the instruction signal is applied to the terminal 30, the relay is activated, contacts 51-53 are contacted and the broadcast audio from terminals 31 and 32 is generated from a speaker 20 of the subscriber 1. When the telephone set is hooked up while the broadcast, the relay 70 is activated with the DC bias between the terminals 31 and 32 and the system is restored to the original state.
JP9509681A 1981-06-19 1981-06-19 Telephone exchanger Pending JPS57210756A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP9509681A JPS57210756A (en) 1981-06-19 1981-06-19 Telephone exchanger

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9509681A JPS57210756A (en) 1981-06-19 1981-06-19 Telephone exchanger

Publications (1)

Publication Number Publication Date
JPS57210756A true JPS57210756A (en) 1982-12-24

Family

ID=14128356

Family Applications (1)

Application Number Title Priority Date Filing Date
JP9509681A Pending JPS57210756A (en) 1981-06-19 1981-06-19 Telephone exchanger

Country Status (1)

Country Link
JP (1) JPS57210756A (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5232210A (en) * 1975-09-05 1977-03-11 Hitachi Ltd Detection system for subscriber response signal

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5232210A (en) * 1975-09-05 1977-03-11 Hitachi Ltd Detection system for subscriber response signal

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