GB591495A - Improvements in telephone substation circuits of the anti-side-tone type - Google Patents
Improvements in telephone substation circuits of the anti-side-tone typeInfo
- Publication number
- GB591495A GB591495A GB10687/44A GB1068744A GB591495A GB 591495 A GB591495 A GB 591495A GB 10687/44 A GB10687/44 A GB 10687/44A GB 1068744 A GB1068744 A GB 1068744A GB 591495 A GB591495 A GB 591495A
- Authority
- GB
- United Kingdom
- Prior art keywords
- line
- direct current
- resistance
- suggested
- impedance
- 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
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/58—Anti-side-tone circuits
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/02—Details
- H04B3/40—Artificial lines; Networks simulating a line of certain length
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/738—Interface circuits for coupling substations to external telephone lines
- H04M1/76—Compensating for differences in line impedance
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Telephone Function (AREA)
- Monitoring And Testing Of Exchanges (AREA)
- Thermistors And Varistors (AREA)
Abstract
591,495. Anti-side-tone circuits. WESTERN ELECTRIC CO., Inc. June 2, 1944, No. 10687. Convention date, Oct. 24, 1942. [Class 40 (iv)] In a substation circuit of the anti-side-tone type, the impedance of the balancing means is changed in accordance with the direct current flowing in the line, so that the balance is automatically adjusted for lines of differing lengths. The variation in impedance may be by a non-linear resistance variable by applied voltage or by heating. In the arrangement shown in Fig. 3, the non-linear resistance 60, comprising two parallel opposed copper oxide elements, is connected across the balancing arm X, C1 and the value of X is chosen to balance a line of maximum anticipated length. If a shorter line is connected to terminals L1, L2, the direct current flowing is greater and this causes the resistance of V to decrease to a point where the combination of X and V again balances the line. Fig. 4 shows an arrangement in which the direct current from the line L1, L2 is passed through a heating coil H, the variation in whose temperature affects the sensitive resistances E1, E2. Various other arrangements are described giving the selective insertion or cutting out of inductive or capacitive branches instead of a simple resistance. Suggested varistors are copper oxide and silicon carbide and suggested thermistors are silver sulphide, uranium oxide and mixtures of metallic oxides.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US463184A US2387269A (en) | 1942-10-24 | 1942-10-24 | Telephone system |
Publications (1)
Publication Number | Publication Date |
---|---|
GB591495A true GB591495A (en) | 1947-08-20 |
Family
ID=23839177
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB10687/44A Expired GB591495A (en) | 1942-10-24 | 1944-06-02 | Improvements in telephone substation circuits of the anti-side-tone type |
Country Status (6)
Country | Link |
---|---|
US (1) | US2387269A (en) |
BE (1) | BE468046A (en) |
ES (1) | ES177484A1 (en) |
FR (1) | FR941331A (en) |
GB (1) | GB591495A (en) |
NL (1) | NL64921C (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE886766C (en) * | 1951-03-03 | 1953-08-17 | Normalzeit G M B H | Device to prevent unauthorized eavesdropping on telephone conversations |
DE1038118B (en) * | 1951-04-26 | 1958-09-04 | Int Standard Electric Corp | Circuit arrangement for telephone stations to prevent overhearing one's own speech and room noise |
DE1039104B (en) * | 1951-04-18 | 1958-09-18 | Int Standard Electric Corp | Circuit arrangement for telephone stations to prevent overhearing one's own speech |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2518178A (en) * | 1947-11-05 | 1950-08-08 | Automatic Elect Lab | Antisidetone and line balancing substation circuits for telephone systems |
BE485032A (en) * | 1947-12-22 | |||
US2568150A (en) * | 1948-06-15 | 1951-09-18 | Bell Telephone Labor Inc | Balancing network for subscribers' telephone sets |
US2604543A (en) * | 1950-11-09 | 1952-07-22 | Bell Telephone Labor Inc | Equalizer circuit |
BE505815A (en) * | 1950-12-27 | |||
BE510745A (en) * | 1951-04-18 | |||
BE539848A (en) * | 1954-07-16 | |||
US3119063A (en) * | 1961-01-13 | 1964-01-21 | Gen Dynamics Corp | Transmission line terminating impedance distinguishing circuit |
DE1928434A1 (en) * | 1969-06-04 | 1970-12-10 | Siemens Ag | Circuit arrangement for connecting direct current data transmission systems with low transmission voltage to a data exchange |
NL7805416A (en) * | 1978-05-19 | 1979-11-21 | Philips Nv | SELF-ADJUSTING FORK GEARS. |
US6146056A (en) * | 1998-01-14 | 2000-11-14 | Jennmar Corporation | Channel and bearing plate assembly |
-
0
- BE BE468046D patent/BE468046A/xx unknown
- NL NL64921D patent/NL64921C/xx active
-
1942
- 1942-10-24 US US463184A patent/US2387269A/en not_active Expired - Lifetime
-
1944
- 1944-06-02 GB GB10687/44A patent/GB591495A/en not_active Expired
-
1947
- 1947-01-30 FR FR941331D patent/FR941331A/en not_active Expired
- 1947-03-18 ES ES0177484A patent/ES177484A1/en not_active Expired
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE886766C (en) * | 1951-03-03 | 1953-08-17 | Normalzeit G M B H | Device to prevent unauthorized eavesdropping on telephone conversations |
DE1039104B (en) * | 1951-04-18 | 1958-09-18 | Int Standard Electric Corp | Circuit arrangement for telephone stations to prevent overhearing one's own speech |
DE1038118B (en) * | 1951-04-26 | 1958-09-04 | Int Standard Electric Corp | Circuit arrangement for telephone stations to prevent overhearing one's own speech and room noise |
Also Published As
Publication number | Publication date |
---|---|
BE468046A (en) | |
NL64921C (en) | |
US2387269A (en) | 1945-10-23 |
FR941331A (en) | 1949-01-07 |
ES177484A1 (en) | 1947-05-01 |
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