JPS57155862A - Line monitoring system - Google Patents

Line monitoring system

Info

Publication number
JPS57155862A
JPS57155862A JP4064481A JP4064481A JPS57155862A JP S57155862 A JPS57155862 A JP S57155862A JP 4064481 A JP4064481 A JP 4064481A JP 4064481 A JP4064481 A JP 4064481A JP S57155862 A JPS57155862 A JP S57155862A
Authority
JP
Japan
Prior art keywords
current
voltage
transmitter
output
circuit
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
JP4064481A
Other languages
Japanese (ja)
Inventor
Kiyotaka Nishi
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 JP4064481A priority Critical patent/JPS57155862A/en
Publication of JPS57155862A publication Critical patent/JPS57155862A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/24—Testing correct operation
    • H04L1/245—Testing correct operation by using the properties of transmission codes
    • H04L1/247—Testing correct operation by using the properties of transmission codes three-level transmission codes, e.g. ternary

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Dc Digital Transmission (AREA)

Abstract

PURPOSE:To discriminate the presence and the absence of line connection without providing a circuit monitoring those at the reception side, by using a current-voltage converter at the transmission side of a voltage signal. CONSTITUTION:The output side of a voltage signal generating source 5 in a transmitter 3 transmitting a voltage signal is provided with a current-voltage converter 6 of positive polarity and a current-voltage converter 7 of a negative polarity. When a transmitter at the reception side is connected, a high level voltage is caused depending on the polarity of a current flowing to the transmission line to the current-voltage converters 6 and 7, an output of an NOR circuit 8 is kept at low level. If the transmitter 4 at the reception side is opened due to open trasmission line or the like, no current flows to the current-voltage converters 6 and 7, the output of the NOR circuit 8 goes to high level, and an alarm signal is produced.
JP4064481A 1981-03-21 1981-03-21 Line monitoring system Pending JPS57155862A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP4064481A JPS57155862A (en) 1981-03-21 1981-03-21 Line monitoring system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4064481A JPS57155862A (en) 1981-03-21 1981-03-21 Line monitoring system

Publications (1)

Publication Number Publication Date
JPS57155862A true JPS57155862A (en) 1982-09-27

Family

ID=12586259

Family Applications (1)

Application Number Title Priority Date Filing Date
JP4064481A Pending JPS57155862A (en) 1981-03-21 1981-03-21 Line monitoring system

Country Status (1)

Country Link
JP (1) JPS57155862A (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4984513A (en) * 1972-12-20 1974-08-14
JPS55138949A (en) * 1979-04-17 1980-10-30 Fujitsu Ltd Open line detection circuit

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4984513A (en) * 1972-12-20 1974-08-14
JPS55138949A (en) * 1979-04-17 1980-10-30 Fujitsu Ltd Open line detection circuit

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