JPS56164695A - Key telephone set - Google Patents
Key telephone setInfo
- Publication number
- JPS56164695A JPS56164695A JP6870680A JP6870680A JPS56164695A JP S56164695 A JPS56164695 A JP S56164695A JP 6870680 A JP6870680 A JP 6870680A JP 6870680 A JP6870680 A JP 6870680A JP S56164695 A JPS56164695 A JP S56164695A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- telephone set
- key telephone
- main device
- power supply
- 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
- 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
- H04M9/003—Transmission of control signals from or to the key telephone set; signalling equipment at key telephone set, e.g. keyboard or display equipment
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Sub-Exchange Stations And Push- Button Telephones (AREA)
Abstract
PURPOSE:To prevent malfunction due to noise at nonconnection of key telephone set, by providing a current detection circuit stopping the data reception operation of main device, if power supply current is absent between a key telephone set and the main device. CONSTITUTION:Between a main device 1 and a key telephone set 2, 2 pairs of lines 6, 11 are connected, and a power supply 15 connected with a current detecting circuit 16 is connected between a data transmission circuit 3 of the main device 1 and a reception circuit 13 at the center of weight of both the lines 6 and 11, and also, between a data reception circuit 8 and a transmission circuit 9 of the key telephone set 2, a power supply circuit 17 is connected. Further, when the key telephone set 2 is detached from the main device 1, the current detecting circuit 16 detects the disconnection and transmits the detection signal to the circuit 13, which stops the reception of data, allowing to avoid the operation due to noise.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6870680A JPS56164695A (en) | 1980-05-22 | 1980-05-22 | Key telephone set |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6870680A JPS56164695A (en) | 1980-05-22 | 1980-05-22 | Key telephone set |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS56164695A true JPS56164695A (en) | 1981-12-17 |
Family
ID=13381479
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP6870680A Pending JPS56164695A (en) | 1980-05-22 | 1980-05-22 | Key telephone set |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS56164695A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008303012A (en) * | 2007-06-06 | 2008-12-18 | Kyocera Mita Corp | Image forming device |
-
1980
- 1980-05-22 JP JP6870680A patent/JPS56164695A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008303012A (en) * | 2007-06-06 | 2008-12-18 | Kyocera Mita Corp | Image forming device |
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