JPS648752A - Signal detection circuit for telephone set - Google Patents
Signal detection circuit for telephone setInfo
- Publication number
- JPS648752A JPS648752A JP16444187A JP16444187A JPS648752A JP S648752 A JPS648752 A JP S648752A JP 16444187 A JP16444187 A JP 16444187A JP 16444187 A JP16444187 A JP 16444187A JP S648752 A JPS648752 A JP S648752A
- Authority
- JP
- Japan
- Prior art keywords
- telephone set
- output
- comparator
- detection circuit
- state
- 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
Landscapes
- Monitoring And Testing Of Exchanges (AREA)
Abstract
PURPOSE:To easily detect the communication state of a telephone set and a call signal by providing a comparing means comparing a potential difference between trunk lines connecting to the telephone set and a state detecting means detecting the state of the comparing means. CONSTITUTION:When an output of a comparator 1 is at 'L' normally, it represents that the telephone set is not busy. When the output of the comparator 1 is normally at 'H', it represents that the telephone set is busy. However when the output of the comparator 1 is logic L, the instant the output goes to logic H synchronously, it is indicated that the telephone set is being called. Thus, a status detection circuit 2 decodes the output of the comparator 1 to easily detect the busy state of the telephone set and a call signal.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16444187A JPS648752A (en) | 1987-07-01 | 1987-07-01 | Signal detection circuit for telephone set |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16444187A JPS648752A (en) | 1987-07-01 | 1987-07-01 | Signal detection circuit for telephone set |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS648752A true JPS648752A (en) | 1989-01-12 |
Family
ID=15793223
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP16444187A Pending JPS648752A (en) | 1987-07-01 | 1987-07-01 | Signal detection circuit for telephone set |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS648752A (en) |
-
1987
- 1987-07-01 JP JP16444187A patent/JPS648752A/en active Pending
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