JPS57190450A - Privacy system for push-button dial telephone set - Google Patents
Privacy system for push-button dial telephone setInfo
- Publication number
- JPS57190450A JPS57190450A JP7534981A JP7534981A JPS57190450A JP S57190450 A JPS57190450 A JP S57190450A JP 7534981 A JP7534981 A JP 7534981A JP 7534981 A JP7534981 A JP 7534981A JP S57190450 A JPS57190450 A JP S57190450A
- Authority
- JP
- Japan
- Prior art keywords
- privacy
- push
- dial telephone
- circuit
- button dial
- 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.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M9/00—Arrangements for interconnection not involving centralised switching
- H04M9/002—Arrangements for interconnection not involving centralised switching with subscriber controlled access to a line, i.e. key telephone systems
- H04M9/005—Arrangements for interconnection not involving centralised switching with subscriber controlled access to a line, i.e. key telephone systems with subscriber controlled access to an exchange line
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Sub-Exchange Stations And Push- Button Telephones (AREA)
Abstract
PURPOSE:To produce a push-button dial telephone set with an extension privacy function in addition to a main wire privary function. CONSTITUTION:In addition to a main wire privacy function, an extension privacy function which is impossible in the ordinary privacy system is provided to subscribers of push-button dial telephone sets by connecting a main wire privacy circuit operated by detecting the voltage of a control line for a main wire circuit, a control line voltage detecting circuit for an extension circuit operated by a comparator, an extension calling status storage operated by a thyrister, and a switch circuit for sending control line voltage operated by a transistor to each bush-button dial telephone set.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7534981A JPS57190450A (en) | 1981-05-19 | 1981-05-19 | Privacy system for push-button dial telephone set |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7534981A JPS57190450A (en) | 1981-05-19 | 1981-05-19 | Privacy system for push-button dial telephone set |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS57190450A true JPS57190450A (en) | 1982-11-24 |
JPH0129119B2 JPH0129119B2 (en) | 1989-06-07 |
Family
ID=13573672
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP7534981A Granted JPS57190450A (en) | 1981-05-19 | 1981-05-19 | Privacy system for push-button dial telephone set |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS57190450A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63217758A (en) * | 1987-03-05 | 1988-09-09 | Nec Corp | Branching telephone set |
-
1981
- 1981-05-19 JP JP7534981A patent/JPS57190450A/en active Granted
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63217758A (en) * | 1987-03-05 | 1988-09-09 | Nec Corp | Branching telephone set |
JPH055421B2 (en) * | 1987-03-05 | 1993-01-22 | Nippon Electric Co |
Also Published As
Publication number | Publication date |
---|---|
JPH0129119B2 (en) | 1989-06-07 |
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