GB584358A - Improvements in or relating to electrical signalling systems - Google Patents
Improvements in or relating to electrical signalling systemsInfo
- Publication number
- GB584358A GB584358A GB2606444A GB2606444A GB584358A GB 584358 A GB584358 A GB 584358A GB 2606444 A GB2606444 A GB 2606444A GB 2606444 A GB2606444 A GB 2606444A GB 584358 A GB584358 A GB 584358A
- Authority
- GB
- United Kingdom
- Prior art keywords
- signalling
- currents
- frequency
- master switch
- cct
- 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.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/54—Systems for transmission via power distribution lines
- H04B3/544—Setting up communications; Call and signalling arrangements
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Emergency Alarm Devices (AREA)
- Alarm Systems (AREA)
Abstract
584,358. Signalling over power circuits. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., and SAVILLE, W. Dec. 29,1944, No. 26064. [Class 40 (iv)] In a signalling system in which high-frequency signalling currents are superimposed on electric supply mains, a test is made immediately prior to signalling to ascertain whether any currents of signalling frequency are present on the line. Any output from the transformer L1, L2, which is tuned to the signalling frequency, is superimposed on the standing voltage on the grid of a gas-filled valve CCT and, if of sufficient amplitude, causes it to fire and operate relay TR. Contact TR1 renders the signalling master switch MS inoperative for as long as the parasitic currents persist, at the same time actuating an audible or visible alarm over lead 14. Alternatively, the glow of the valve CCT may be used as an indicator. If there are no parasitic currents on the mains when the master switch is first operated, relay MSR operates and locks over MSR1 while MSR2 initiates signalling. Thus, disturbances occurring during signalling have no effect. The master switch MS can be made to open a point in lead 14 to prevent an alarm being given by signalling currents and switching can be incorporated at points 10, 11, 12, 13 to make the equipment responsive to other desired frequencies. A contact voltmeter as described in Specification 580,393 may be substituted for the gas-filled valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2606444A GB584358A (en) | 1944-12-29 | 1944-12-29 | Improvements in or relating to electrical signalling systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2606444A GB584358A (en) | 1944-12-29 | 1944-12-29 | Improvements in or relating to electrical signalling systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB584358A true GB584358A (en) | 1947-01-13 |
Family
ID=10237797
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB2606444A Expired GB584358A (en) | 1944-12-29 | 1944-12-29 | Improvements in or relating to electrical signalling systems |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB584358A (en) |
-
1944
- 1944-12-29 GB GB2606444A patent/GB584358A/en not_active Expired
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