GB472993A - Improvements in or relating to alternating current signalling systems - Google Patents
Improvements in or relating to alternating current signalling systemsInfo
- Publication number
- GB472993A GB472993A GB988336A GB988336A GB472993A GB 472993 A GB472993 A GB 472993A GB 988336 A GB988336 A GB 988336A GB 988336 A GB988336 A GB 988336A GB 472993 A GB472993 A GB 472993A
- Authority
- GB
- United Kingdom
- Prior art keywords
- relay
- circuits
- release
- relating
- alternating current
- 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
- H04Q—SELECTING
- H04Q1/00—Details of selecting apparatus or arrangements
- H04Q1/18—Electrical details
- H04Q1/30—Signalling arrangements; Manipulation of signalling currents
- H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
- H04Q1/442—Signalling arrangements; Manipulation of signalling currents using alternate current with out-of-voice band signalling frequencies
- H04Q1/4423—Signalling arrangements; Manipulation of signalling currents using alternate current with out-of-voice band signalling frequencies using one signalling frequency
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Interface Circuits In Exchanges (AREA)
Abstract
472,993. Automatic exchange systems. STANDARD TELEPHONES & CABLES. Ltd., and BOWSHER, E. A. H. April 3, 1936, No. 9883. [Class 40 (iv)] The release of a call at a main exchange MX is signalled over a junction to a P.B.X. by changing the relative impedance of the leg circuits to which A.C. is connected in parallel at the P.B.X. so as to operate a relay AC having a winding included in each circuit, as in Fig. 1, or bridging the circuits, as in Fig. 2. Relay AC is shunted by a rectifier MR, and the A.C. is applied to the leg circuits through condensers by a relay X (not shown) upon release at the P.B.X. Since the circuits at first include the equal impedance windings of relay D, no effect is produced. When release occurs at the main exchange, one circuit is connected to relay L while the other is directly earthed, so that a difference of potential across relay AC causes its operation. If relay L is of low impedance, the operation. may be improved by a rectifier MRB in series therewith.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB988336A GB472993A (en) | 1936-04-03 | 1936-04-03 | Improvements in or relating to alternating current signalling systems |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB988336A GB472993A (en) | 1936-04-03 | 1936-04-03 | Improvements in or relating to alternating current signalling systems |
Publications (1)
Publication Number | Publication Date |
---|---|
GB472993A true GB472993A (en) | 1937-10-04 |
Family
ID=9880562
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB988336A Expired GB472993A (en) | 1936-04-03 | 1936-04-03 | Improvements in or relating to alternating current signalling systems |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB472993A (en) |
-
1936
- 1936-04-03 GB GB988336A patent/GB472993A/en not_active Expired
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