GB1344794A - Isolation equipment for telegraphic apparatus - Google Patents

Isolation equipment for telegraphic apparatus

Info

Publication number
GB1344794A
GB1344794A GB1344794DA GB1344794A GB 1344794 A GB1344794 A GB 1344794A GB 1344794D A GB1344794D A GB 1344794DA GB 1344794 A GB1344794 A GB 1344794A
Authority
GB
United Kingdom
Prior art keywords
transistor
point
current
conduct
resistor
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
Application number
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ITT Creed Ltd
Original Assignee
ITT Creed Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by ITT Creed Ltd filed Critical ITT Creed Ltd
Publication of GB1344794A publication Critical patent/GB1344794A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/20—Repeater circuits; Relay circuits
    • H04L25/26—Circuits with optical sensing means, i.e. using opto-couplers for isolation

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Led Devices (AREA)
  • Optical Communication System (AREA)

Abstract

1344794 Telegraphy; isolating arrangements ITT CREED Ltd 20 July 1972 34019/72 Heading H4P An arrangement providing a sharp threshold characteristic for a light emitting device 16 in a line isolating circuit comprises a pair of differentially arranged transistors 1, 2. With zero line current both transistors are non-conductive but as current rises transistor 1 will begin to conduct up to the point that Zener diode 6 breaks down. With further rise in line current, voltage at point 12 will exceed that at point 4 hence transistor 2 will start to conduct and due to the differential connection will rapidly reach full conduction hence causing light emitter 16 to glow and transistor 1 to be shut off. More rapid changeover may be caused by positive feedback resistors 18, 19. To provide a variable threshold, resistor 19 may be connected to a sliding contact of a resistor (not shown) connected between resistors 13, 14. Zener diode 6 may be replaced by any element or combination giving a volt drop independent of current, e.g. a diode chain.
GB1344794D 1972-07-20 1972-07-20 Isolation equipment for telegraphic apparatus Expired GB1344794A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3401972 1972-07-20

Publications (1)

Publication Number Publication Date
GB1344794A true GB1344794A (en) 1974-01-23

Family

ID=10360365

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1344794D Expired GB1344794A (en) 1972-07-20 1972-07-20 Isolation equipment for telegraphic apparatus

Country Status (4)

Country Link
DE (1) DE2336137A1 (en)
FR (1) FR2194090A1 (en)
GB (1) GB1344794A (en)
IT (1) IT991123B (en)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1290562C2 (en) * 1965-03-23 1976-09-23 Siemens AG, 1000 Berlin und 8000 München CIRCUIT ARRANGEMENT FOR TRANSFERRING DC IMPULSES
FR2146946B1 (en) * 1971-07-27 1974-03-29 Lignes Telegraph Telephon
DE2159760C3 (en) * 1971-12-02 1979-11-15 Deutsche Itt Industries Gmbh, 7800 Freiburg Electronic threshold switch

Also Published As

Publication number Publication date
IT991123B (en) 1975-07-30
DE2336137A1 (en) 1974-01-31
FR2194090A1 (en) 1974-02-22

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Legal Events

Date Code Title Description
PS Patent sealed
435 Patent endorsed 'licences of right' on the date specified (sect. 35/1949)
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee