SE420555B - Anordning for kontroll av till en abonnentapparat kommande telefonanrop - Google Patents

Anordning for kontroll av till en abonnentapparat kommande telefonanrop

Info

Publication number
SE420555B
SE420555B SE8000586A SE8000586A SE420555B SE 420555 B SE420555 B SE 420555B SE 8000586 A SE8000586 A SE 8000586A SE 8000586 A SE8000586 A SE 8000586A SE 420555 B SE420555 B SE 420555B
Authority
SE
Sweden
Prior art keywords
frequencies
frequency
subscriber
relay
signal
Prior art date
Application number
SE8000586A
Other languages
English (en)
Swedish (sv)
Other versions
SE8000586L (sv
Inventor
Toledo Pierre De
Original Assignee
Toledo Pierre De
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 Toledo Pierre De filed Critical Toledo Pierre De
Publication of SE8000586L publication Critical patent/SE8000586L/
Publication of SE420555B publication Critical patent/SE420555B/sv

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/66—Substation equipment, e.g. for use by subscribers with means for preventing unauthorised or fraudulent calling
    • H04M1/663—Preventing unauthorised calls to a telephone set
    • H04M1/665—Preventing unauthorised calls to a telephone set by checking the validity of a code

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Signal Processing (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Telephonic Communication Services (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Monitoring And Testing Of Exchanges (AREA)
  • Alarm Systems (AREA)
  • Devices For Supply Of Signal Current (AREA)
SE8000586A 1978-05-30 1980-01-25 Anordning for kontroll av till en abonnentapparat kommande telefonanrop SE420555B (sv)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH587878A CH623695A5 (fr) 1978-05-30 1978-05-30

Publications (2)

Publication Number Publication Date
SE8000586L SE8000586L (sv) 1980-01-25
SE420555B true SE420555B (sv) 1981-10-12

Family

ID=4300837

Family Applications (1)

Application Number Title Priority Date Filing Date
SE8000586A SE420555B (sv) 1978-05-30 1980-01-25 Anordning for kontroll av till en abonnentapparat kommande telefonanrop

Country Status (5)

Country Link
CH (1) CH623695A5 (fr)
FR (1) FR2427748A1 (fr)
GB (1) GB2037540B (fr)
SE (1) SE420555B (fr)
WO (1) WO1979001145A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4439638A (en) * 1982-01-28 1984-03-27 International Mobile Machines Corp. Sound-activated code-controlled detection system for telephones and the like
GB2203614A (en) * 1987-04-09 1988-10-19 British Broadcasting Corp Control of access to a telephone
GB2240903B (en) * 1990-02-13 1994-07-13 Proton Communications Automatic telephone call interceptor and interrogator devices

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3829616A (en) * 1974-06-28 1974-08-13 Int Mobile Machines Ringer blocking attachment for telephones

Also Published As

Publication number Publication date
FR2427748B1 (fr) 1982-06-11
GB2037540B (en) 1982-08-18
CH623695A5 (fr) 1981-06-15
GB2037540A (en) 1980-07-09
FR2427748A1 (fr) 1979-12-28
WO1979001145A1 (fr) 1979-12-27
SE8000586L (sv) 1980-01-25

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