JPS57155862A - Line monitoring system - Google Patents
Line monitoring systemInfo
- 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
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.
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)
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 |
-
1981
- 1981-03-21 JP JP4064481A patent/JPS57155862A/en active Pending
Patent Citations (2)
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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