JPS5742293A - Loop detection system - Google Patents

Loop detection system

Info

Publication number
JPS5742293A
JPS5742293A JP11872180A JP11872180A JPS5742293A JP S5742293 A JPS5742293 A JP S5742293A JP 11872180 A JP11872180 A JP 11872180A JP 11872180 A JP11872180 A JP 11872180A JP S5742293 A JPS5742293 A JP S5742293A
Authority
JP
Japan
Prior art keywords
voltage
connecting point
loop circuit
line
telephone set
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
JP11872180A
Other languages
Japanese (ja)
Inventor
Yukio Kobayashi
Eiji Minamitani
Moriyoshi Ishida
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.)
Fujitsu Ltd
Original Assignee
Fujitsu 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 Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP11872180A priority Critical patent/JPS5742293A/en
Publication of JPS5742293A publication Critical patent/JPS5742293A/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)
  • Interface Circuits In Exchanges (AREA)

Abstract

PURPOSE:To accurately detect the width of dial pulse without the effect of lines, by storing a voltage at loop circuit closing due to telephone set off-hook through division and controlling the closing or interruption of the loop circuit according to the result of comparison between this voltage and at a voltage at connecting point. CONSTITUTION:A loop circuit is formed with choke coils CH1, CH2 constituting a feeding circuit, resistors R1, R2, line L and telephone set T, and a current flows to the telephone set T with the feeding circuit. An operational amplifier OP1 in voltage follower connectioon is connected to a connecting point (a) between the choke CH2 of this feeding circuit and the line L, a voltage at loop closing by the telephone off-hook is divided into 1/N with resistors R4, R5 and the voltage is stored in a capacitor C. This voltage is applied to a photo coupler PC via an operational amplifier OP2, it is compared with a voltage at the connecting point (a) outputted from the amplifier OP1, and a loop circuit is closed when the potential at the connecting point (a) is higher and opened when lower, allowing to exclude the effect of resistance value of the line L.
JP11872180A 1980-08-28 1980-08-28 Loop detection system Pending JPS5742293A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP11872180A JPS5742293A (en) 1980-08-28 1980-08-28 Loop detection system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11872180A JPS5742293A (en) 1980-08-28 1980-08-28 Loop detection system

Publications (1)

Publication Number Publication Date
JPS5742293A true JPS5742293A (en) 1982-03-09

Family

ID=14743433

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11872180A Pending JPS5742293A (en) 1980-08-28 1980-08-28 Loop detection system

Country Status (1)

Country Link
JP (1) JPS5742293A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0319679A (en) * 1989-06-14 1991-01-28 Miyasaka Jozo Kk Solidification of instant food
US8593799B2 (en) 2010-05-19 2013-11-26 Sony Corporation Stand and display device including stand

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0319679A (en) * 1989-06-14 1991-01-28 Miyasaka Jozo Kk Solidification of instant food
US8593799B2 (en) 2010-05-19 2013-11-26 Sony Corporation Stand and display device including stand

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