EP0338654A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for controlling communication by a modem over a telephone line
Assignee: Control Data Corp
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Filing: 1989-01-05
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Granted: —
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Expires: 2009-01-05
Abstract
Abstract A method and apparatus are provided for use in an automatic tele-communication system for controlling communication by a modem over a telephone line. Means (R13, D6, U2, R25, 11; D101, D102, D103, U106, R101, 11) are provided for determining prior to initiating communication by the modem over the telephone line whether a telephone connected to the telephone line is off hook and for inhibiting communication by the modem over the telephone line if a telephone is off hook. These same means or further means (11, R59, C32, R51, R55, C29, R54, R52, U11) are arranged for determining during communication by the modem over the telephone line whether a telephone connected to the telephone line goes off hook and for terminating such communication if a telephone goes off hook so as to release the telephone line for use by the telephone.
Inventors
- 👤 Joseph Andrew Damoci
- 👤 Matthew Ford Kern
- 👤 Russell James Welsh
- 👤 John Dignus Fourdraine
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 07:15
CPC Classifications
H; H04; H04M; H04M11/00; H04M11/06
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
95 words
Apparatus for use in an automatic telecommunication system for controlling communication by a modem over a telephone line, the apparatus being characterised by means (R13, D6, U2, R25, 11, R59, C32, R51, R55, C29, R52, R54, U11; D101, D102, D103, U106, R101, 11) for determining whether a telephone connected to the telephone line is or goes off hook and for inhibiting or terminating communication by the modem over the telephone line if it is determined that a telephone is or goes off hook so as to allow use of the telephone line by the telephone.
Claim 2
Dependent Claim
95 words
Apparatus for use in an automatic telecommunication system for controlling communication by a modem over a telephone line, the apparatus being characterised by means (R13, D6, U2, R25, 11, R59, C32, R51, R55, C29, R52, R54, U11; D101, D102, D103, U106, R101, 11) for determining whether a telephone connected to the telephone line is or goes off hook and for inhibiting or terminating communication by the modem over the telephone line if it is determined that a telephone is or goes off hook so as to allow use of the telephone line by the telephone.
Claim 3
Dependent Claim
52 words
Apparatus as claimed in claim 1, characterised in that the determining means comprise means (D101, D102, D103) for deriving a standard voltage signal from a voltage on the telephone line, and means (U106) responsive to disappearance of the standard voltage signal for providing an indication that a telephone has gone off hook.
Claim 4
Dependent Claim
51 words
Apparatus as claimed in claim 2, characterised in that the means for deriving the standard voltage signal comprise a Zener diode (D101) selected to have a voltage rating in comparison with the voltage on the telephone line such that, when a telephone goes off hook, the Zener diode no longer conducts.
Claim 5
Dependent Claim
58 words
Apparatus as claimed in claim 2 or 3, characterised in that the means for deriving the standard voltage signal comprise a plurality of Zener diodes (D101, D102, D103), each having a different voltage rating and being arranged to be selectively employed for deriving the standard voltage signal in dependance upon the normal voltage on the particular telephone line.
Claim 6
Dependent Claim
101 words
Apparatus according to claim 1, characterised in that the determining means comprise first and second integrators (R59, C32, R51, R55, C29, R52, R54) having respectively relatively short and long integration time constants and being arranged to integrate a signal which is transmitted on the telephone line during communication by the modem over the telephone line, and comparison means (U11) for comparing the integrated signal outputs of the first and second integrators in order to detect a substantial difference between the integrated signal outputs indicative of an additional load being applied to the telephone line corresponding to a telephone going off hook.
Claim 7
Dependent Claim
67 words
Apparatus as claimed in claim 5, characterised by means (11, R24, R36, R37, R26, C24, C18, C19, C20, U6, R40, R41, U8, U9, C21 to C23, R32 to R34, R27, R28) for generating a test signal and for supplying the test signal to the telephone line during communication by the modem over the telephone line, the first and second integrators being arranged to integrate the test signal.
Claim 8
Dependent Claim
25 words
Apparatus as claimed in claim 5, characterised in that the first and second integrators are arranged to integrate the data signal transmitted by the modem.
Claim 9
Independent Claim
101 words
A method of controlling communication by a modem over a telephone line in an automatic tele-communication system, characterised by the steps of determining prior to initiating communication by the modem over the telephone line whether a telephone is off hook and inhibiting communication by the modem over the telephone line if a telephone is off hook, and determining during communication by the modem over the telephone line whether a telephone goes off hook and terminating communication by the modem over the telephone line if a telephone goes off hook so as to release the telephone line for use by the telephone.
Claim 10
Independent Claim
101 words
A method of controlling communication by a modem over a telephone line in an automatic tele-communication system, characterised by the steps of determining prior to initiating communication by the modem over the telephone line whether a telephone is off hook and inhibiting communication by the modem over the telephone line if a telephone is off hook, and determining during communication by the modem over the telephone line whether a telephone goes off hook and terminating communication by the modem over the telephone line if a telephone goes off hook so as to release the telephone line for use by the telephone.
Claim 11
Dependent Claim
64 words
A method as claimed in claim 8, characterised in that the step of determining during communication by the modem over the telephone line comprises the steps of deriving a standard voltage signal from a voltage on the telephone line, and responding to a substantial change in or disappearance of said standard voltage signal to provide an indication that a telephone has gone off hook.
Claim 12
Dependent Claim
101 words
A method as claimed in claim 8, characterised in that the step of determining during communication by the modem over the telephone line comprises the steps of integrating a signal supplied to the telephone line during communication by the modem over the telephone line in first and second integrators (R59, C32, R51, R55, C29, R52, R54) having respectively relatively short and long integration time constants, and comparing the outputs of the first and second integrators to detect a substantial difference between the outputs indicative of an additional load being applied to the telephone line corresponding to a telephone going off hook.
Claim 13
Dependent Claim
40 words
A method as claimed in claim 10, characterised by the step of generating a test signal for supply to the telephone line during communication by the modem over the telephone line and for integration by the first and second integrators.
Claim 14
Dependent Claim
36 words
A method as claimed in claim 10, characterised in that the data signal transmitted by the modem during communication by the modem over the telephone line is the signal integrated by the first and second integrators.
References Cited (Backward Citations)
No citation records indexed.
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