JPS556999A - Privacy circuit of key telephone system - Google Patents
Privacy circuit of key telephone systemInfo
- Publication number
- JPS556999A JPS556999A JP8510079A JP8510079A JPS556999A JP S556999 A JPS556999 A JP S556999A JP 8510079 A JP8510079 A JP 8510079A JP 8510079 A JP8510079 A JP 8510079A JP S556999 A JPS556999 A JP S556999A
- Authority
- JP
- Japan
- Prior art keywords
- relay
- privacy
- key telephone
- winding
- telephone 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.)
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Sub-Exchange Stations And Push- Button Telephones (AREA)
Abstract
PURPOSE:To obtain a privacy circuit for the key telephone system in order to secure the use of two pieces of control lines for other purposes than the privacy talk. CONSTITUTION:The key telephone sets TEL0 and TEL1 consist of connection terminals l1, l2, h1 and h2to main unit 1; telephone circuit network N; fixed switches HS<0> and HS<1>; winding S for the privacy-use relay; relay K comprising contacts s<0> and s<1> of relay S, primary winding K(P), secondary winding K(S) plus contact k; diodes D1-D5; transistor Tr1, resistances R1-R4; and capacitors C1 and C2. While unit 1 consists of detection circuit DET, primary winding H(D), secondary winding H(S), relay H for polarity inversion comprising contacts h<0>- h<3>, transistor Tr0, resistances R0 and R10, diode D0 and capacitor C0 respectively.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8510079A JPS593913B2 (en) | 1979-07-06 | 1979-07-06 | Confidential relay drive circuit in button telephone equipment |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8510079A JPS593913B2 (en) | 1979-07-06 | 1979-07-06 | Confidential relay drive circuit in button telephone equipment |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP8967375A Division JPS5213707A (en) | 1975-07-23 | 1975-07-24 | Privacy system in key telephone system |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS556999A true JPS556999A (en) | 1980-01-18 |
JPS593913B2 JPS593913B2 (en) | 1984-01-26 |
Family
ID=13849184
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP8510079A Expired JPS593913B2 (en) | 1979-07-06 | 1979-07-06 | Confidential relay drive circuit in button telephone equipment |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS593913B2 (en) |
-
1979
- 1979-07-06 JP JP8510079A patent/JPS593913B2/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
JPS593913B2 (en) | 1984-01-26 |
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