JPS5680952A - Subscriber monitoring circuit - Google Patents

Subscriber monitoring circuit

Info

Publication number
JPS5680952A
JPS5680952A JP15770079A JP15770079A JPS5680952A JP S5680952 A JPS5680952 A JP S5680952A JP 15770079 A JP15770079 A JP 15770079A JP 15770079 A JP15770079 A JP 15770079A JP S5680952 A JPS5680952 A JP S5680952A
Authority
JP
Japan
Prior art keywords
frequency
pass filter
voltage
switches
differential amplifier
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
JP15770079A
Other languages
Japanese (ja)
Other versions
JPS6232860B2 (en
Inventor
Kunio Nagashima
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 JP15770079A priority Critical patent/JPS5680952A/en
Publication of JPS5680952A publication Critical patent/JPS5680952A/en
Publication of JPS6232860B2 publication Critical patent/JPS6232860B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H04Q1/30—Signalling arrangements; Manipulation of signalling currents
    • H04Q1/32—Signalling arrangements; Manipulation of signalling currents using trains of dc pulses

Abstract

PURPOSE:To simplify hardware constitution by making it possible to control the cut-off frequency of a low-pass filter by a clock frequency. CONSTITUTION:Clock frequency f1 of the 1st clock generating circuit 321 is so set to an adequate value that switches capacity low-pass filter 316 can remove sufficiently an AC voltage depending upon a ringer signal outputted from differential amplifier 315. For this purpose, only a DC voltage that corresponds to the electromotive force of accumulator 307 is appled to one input of voltage comparing circuit 319. To receive dial pulses from a calling subscriber, switches 310, 305 and 320 are placed at the opposite sides to those in the figure. Frequency f2 of the 2nd clock generating circuit 322 is so set that switched capacity low-pass filter 316 can transfer sufficiently a dial pulse waveform, obtained in the output of differential amplifier 315, to voltage comparing circuit 319.
JP15770079A 1979-12-05 1979-12-05 Subscriber monitoring circuit Granted JPS5680952A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15770079A JPS5680952A (en) 1979-12-05 1979-12-05 Subscriber monitoring circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15770079A JPS5680952A (en) 1979-12-05 1979-12-05 Subscriber monitoring circuit

Publications (2)

Publication Number Publication Date
JPS5680952A true JPS5680952A (en) 1981-07-02
JPS6232860B2 JPS6232860B2 (en) 1987-07-17

Family

ID=15655458

Family Applications (1)

Application Number Title Priority Date Filing Date
JP15770079A Granted JPS5680952A (en) 1979-12-05 1979-12-05 Subscriber monitoring circuit

Country Status (1)

Country Link
JP (1) JPS5680952A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58207758A (en) * 1982-03-24 1983-12-03 シ・エツセ・エ・エレ・チ・セントロ・ステユデイ・エ・ラボラトリ・テレコミニカチオ−ニ・エツセ・ピ−・ア− Receiver pickup detecting circuit
JPS6269759A (en) * 1985-09-20 1987-03-31 Matsushita Electric Ind Co Ltd Off-hook condition defecting circuit for telephone exchange
JPH04238448A (en) * 1991-01-23 1992-08-26 Nec Corp Ring trip circuit

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58207758A (en) * 1982-03-24 1983-12-03 シ・エツセ・エ・エレ・チ・セントロ・ステユデイ・エ・ラボラトリ・テレコミニカチオ−ニ・エツセ・ピ−・ア− Receiver pickup detecting circuit
JPS6269759A (en) * 1985-09-20 1987-03-31 Matsushita Electric Ind Co Ltd Off-hook condition defecting circuit for telephone exchange
JPH0452024B2 (en) * 1985-09-20 1992-08-20 Matsushita Electric Ind Co Ltd
JPH04238448A (en) * 1991-01-23 1992-08-26 Nec Corp Ring trip circuit

Also Published As

Publication number Publication date
JPS6232860B2 (en) 1987-07-17

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