JPS56122591A - Subscriber's circuit of telephone switchboard - Google Patents

Subscriber's circuit of telephone switchboard

Info

Publication number
JPS56122591A
JPS56122591A JP2532580A JP2532580A JPS56122591A JP S56122591 A JPS56122591 A JP S56122591A JP 2532580 A JP2532580 A JP 2532580A JP 2532580 A JP2532580 A JP 2532580A JP S56122591 A JPS56122591 A JP S56122591A
Authority
JP
Japan
Prior art keywords
subscriber
call signal
circuit
line loop
relay
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
JP2532580A
Other languages
Japanese (ja)
Inventor
Shinichi Iribe
Shiro Enami
Yuichi Morikawa
Hideyuki Koike
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.)
Hitachi Ltd
Nippon Telegraph and Telephone Corp
Original Assignee
Hitachi Ltd
Nippon Telegraph and Telephone Corp
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 Hitachi Ltd, Nippon Telegraph and Telephone Corp filed Critical Hitachi Ltd
Priority to JP2532580A priority Critical patent/JPS56122591A/en
Publication of JPS56122591A publication Critical patent/JPS56122591A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M19/00—Current supply arrangements for telephone systems
    • H04M19/001—Current supply source at the exchanger providing current to substations
    • H04M19/003—Arrangements for compensation of the DC flux in line transformers

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Signal Processing (AREA)
  • Interface Circuits In Exchanges (AREA)

Abstract

PURPOSE:To attain economization by making it easy to set the same detection threshold level, by holding an input to a subscriber's line loop detecting circuit during call signal transmission at the same level with that to the subscriber's line loop detecting circuit during calling, disconnection and dial pulse reception. CONSTITUTION:When the loop of a subscriber's line is monitored with an electric current flowing through the tertiary winding of hybrid coil 11, a call signal is sent out through the intermittence of a sending relay and during the call signal transmission, an output to circuit 19 which detects the existence of the subscriber's line loop is varied by switching contact 23 of the relay for transmitting the call signal. During origination, disconnection and service other than the call signal transmission, it is held at the same level with an input to circuit 19, so that the subscriber's line loop can be monitored with the same detection threshold level. Therefore, while relays are not increased, this purpose can be attained by adding one resistance and by changing one of contacts of the relay for transmitting the call signal from a make contact to a transfer contact.
JP2532580A 1980-03-03 1980-03-03 Subscriber's circuit of telephone switchboard Pending JPS56122591A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2532580A JPS56122591A (en) 1980-03-03 1980-03-03 Subscriber's circuit of telephone switchboard

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2532580A JPS56122591A (en) 1980-03-03 1980-03-03 Subscriber's circuit of telephone switchboard

Publications (1)

Publication Number Publication Date
JPS56122591A true JPS56122591A (en) 1981-09-26

Family

ID=12162806

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2532580A Pending JPS56122591A (en) 1980-03-03 1980-03-03 Subscriber's circuit of telephone switchboard

Country Status (1)

Country Link
JP (1) JPS56122591A (en)

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