JPS54112109A - Ring trip system - Google Patents

Ring trip system

Info

Publication number
JPS54112109A
JPS54112109A JP2015378A JP2015378A JPS54112109A JP S54112109 A JPS54112109 A JP S54112109A JP 2015378 A JP2015378 A JP 2015378A JP 2015378 A JP2015378 A JP 2015378A JP S54112109 A JPS54112109 A JP S54112109A
Authority
JP
Japan
Prior art keywords
call signal
ring trip
tone source
voltage
trip system
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
JP2015378A
Other languages
Japanese (ja)
Inventor
Naohiko Yasui
Akira Kikuchi
Takuji Mukaemachi
Toshiaki Toyama
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 JP2015378A priority Critical patent/JPS54112109A/en
Publication of JPS54112109A publication Critical patent/JPS54112109A/en
Pending legal-status Critical Current

Links

Landscapes

  • Devices For Supply Of Signal Current (AREA)

Abstract

PURPOSE: To realize easily the electronic ring trip function of the ring trip system of a telephone switchboard by periodically detecting a call signal voltage at a constant voltage level point which is higher than a call signal voltage at the off-hook time and lower than that an on-hook time.
CONSTITUTION: In the ring trip system which discriminates whether a called subscriber answers or not by sending out a call signal from ringing-tone source IR to telephone set SUB of the called subscriber, level detector AA is connected to resistance R0 via tone source IR so as to detect voltage levels of subscriber's lines L1 and L2 at the periodical point in time when the call signal from tone source IR constant in level. Further, this system is equipped with guard timing supply circuit MM which detects the malfunction of detector AA judging from rush current generated at lines L1 and L2 when a trunk pattern is changed over, and zero-cross circuit BB and AND circuit LL which detect the periodical point when the call signal from tone source IR becomes constant in voltage level, thereby constituting the ring trip system.
COPYRIGHT: (C)1979,JPO&Japio
JP2015378A 1978-02-23 1978-02-23 Ring trip system Pending JPS54112109A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2015378A JPS54112109A (en) 1978-02-23 1978-02-23 Ring trip system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2015378A JPS54112109A (en) 1978-02-23 1978-02-23 Ring trip system

Publications (1)

Publication Number Publication Date
JPS54112109A true JPS54112109A (en) 1979-09-01

Family

ID=12019200

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2015378A Pending JPS54112109A (en) 1978-02-23 1978-02-23 Ring trip system

Country Status (1)

Country Link
JP (1) JPS54112109A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5728457A (en) * 1980-07-28 1982-02-16 Nec Corp Ring trip circuit
US5293420A (en) * 1992-03-19 1994-03-08 Fujitsu Limited Ring trip circuit

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5099009A (en) * 1973-12-28 1975-08-06
JPS52107709A (en) * 1976-03-08 1977-09-09 Nakayo Telecommunications System for preventing erroneous trip

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5099009A (en) * 1973-12-28 1975-08-06
JPS52107709A (en) * 1976-03-08 1977-09-09 Nakayo Telecommunications System for preventing erroneous trip

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5728457A (en) * 1980-07-28 1982-02-16 Nec Corp Ring trip circuit
US5293420A (en) * 1992-03-19 1994-03-08 Fujitsu Limited Ring trip circuit

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