US3597551A
Expired / Lapsed
US
⏱️ 0.0 years remaining
In-band signalling apparatus
Assignee: Nokia of America Corp
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Filing: 1969-05-29
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Granted: 1971-08-03
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Expires: 1989-05-29
Abstract
Abstract Improved in-band signalling apparatus useful in the conversion of O-type frequency division multiplexing equipment for the multiplexing of rural subscriber lines is disclosed Specifically, a ring-signal-to-voice-frequency-signal converter is described which is fully transistorized for battery operation from the 48volt battery supply of the telephone system and contains no circuit dependent on external AC power for operation. Furthermore, there is provision for transient-free frequency switching, and the circuit is suitable for use in small fully enclosed spaces. Local generation of the ringing signal is provided to obtain complete separation of the ring detection circuit from the subscriber line.
Inventors
- 👤 Knut Arneberg
- 👤 James R Gibbens
- 👤 Klaus E Funke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:47
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/14; H04; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/44; H04Q1/444; H04Q1/45; H04Q1/453; H04Q11/00; H04Q11/02
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
74 words
In-band subscriber signalling equipment for frequency division multiplexed systems, comprising: a. ring identification circuit means; and b. switching means responsive to the ring identification made by said circuit means to produce a selected ring on the subscriber line; c. said ring identification circuit means being electrically isolated from said subscriber line, and including a plurality of frequency recognition means, and means to disable said frequency recognition means when said subscriber line is off hook.
Claim 2
Dependent Claim
74 words
In-band subscriber signalling equipment for frequency division multiplexed systems, comprising: a. ring identification circuit means; and b. switching means responsive to the ring identification made by said circuit means to produce a selected ring on the subscriber line; c. said ring identification circuit means being electrically isolated from said subscriber line, and including a plurality of frequency recognition means, and means to disable said frequency recognition means when said subscriber line is off hook.
Claim 3
Dependent Claim
24 words
Equipment according to claim 1, in which means are provided to prevent ringing signal current from being transmitted to said ring identification circuit means.
Claim 4
Dependent Claim
26 words
Equipment according to claim 1, in which said disabling means are provided with sufficient off-delay to prevent re-enabling of said frequency recognition means during dial pulses.
Claim 5
Dependent Claim
36 words
Equipment accordIng to claim 1, further comprising on-hook tone signal generating means, and in which said disabling means are actuated by the disabling of said tone signal generating means when said subscriber line goes off hook.
Claim 6
Dependent Claim
20 words
Equipment according to claim 4, in which said on-hook tone signal generating means is independent of AC power line frequency.
Claim 7
Dependent Claim
101 words
In-band signalling apparatus for connecting a frequency-division multiplexed telephone line to a subscriber line, comprising: a. frequency recognition means arranged to sense the presence on said telephone line of a ringing signal composed of predetermined frequencies representing ring code information and to produce an output representative of said code; b. ring-establishing means responsive to said output of said frequency recognition means for establishing a ring on said subscriber line in accordance with said code; and c. disabling means responsive to an off-hook condition on said subscriber line in the absence of said ringing signal for preventing operation of said ring-establishing means.
Claim 8
Dependent Claim
101 words
In-band signalling apparatus for connecting a frequency-division multiplexed telephone line to a subscriber line, comprising: a. frequency recognition means arranged to sense the presence on said telephone line of a ringing signal composed of predetermined frequencies representing ring code information and to produce an output representative of said code; b. ring-establishing means responsive to said output of said frequency recognition means for establishing a ring on said subscriber line in accordance with said code; and c. disabling means responsive to an off-hook condition on said subscriber line in the absence of said ringing signal for preventing operation of said ring-establishing means.
Claim 9
Dependent Claim
16 words
The apparatus of claim 6, in which said disabling means operate to disable said frequency-recognition means.
Claim 10
Dependent Claim
28 words
The apparatus of claim 6, further comprising, delay means associated with said disabling means for maintaining said disabling means in operation during dial pulses on said subscriber line.
Claim 11
Dependent Claim
93 words
In-band signalling apparatus for converting ringing signals to transient-free voice frequency codes, comprising: a. oscillator means arranged to oscillate at a first predetermined frequency; b. reactance means; c. resistance-bridged unity gain amplifier means connected between said oscillator means and said reactance means in such a manner as to cause said oscillator means to oscillate at a second predetermined frequency when said unity gain amplifier means is energized; and d. means for energizing and deenergizing said unity gain amplifier means at a third predetermined frequency substantially lower than said first and second predetermined frequencies.
Claim 12
Dependent Claim
93 words
In-band signalling apparatus for converting ringing signals to transient-free voice frequency codes, comprising: a. oscillator means arranged to oscillate at a first predetermined frequency; b. reactance means; c. resistance-bridged unity gain amplifier means connected between said oscillator means and said reactance means in such a manner as to cause said oscillator means to oscillate at a second predetermined frequency when said unity gain amplifier means is energized; and d. means for energizing and deenergizing said unity gain amplifier means at a third predetermined frequency substantially lower than said first and second predetermined frequencies.
Claim 13
Dependent Claim
34 words
The apparatus of claim 9, in which said third predetermined frequency is a multiple of the 60-cycle commercial power line frequency, but is derived from the telephone system battery independently of said power line.
Claim 14
Dependent Claim
176 words
Apparatus for producing a delayed operation of a relay in response to the appearance of one or more of a plurality of predetermined frequencies on a telephone line, comprising: a. a plurality of frequency signal recognition means each arranged to produce an output during the presence of one of said predetermined frequency signals on said line; b. level detection means responsive to the presence of one or more of said outputs to produce a fixed-level DC enabling signal; c. means for producing a current pulse at the beginning of said enabling signal; d. delay means for maintaining said enabling signal for a predetermined time following the total cessation of said outputs; e. bistable multivibrator means arranged to produce an output when triggered but only while said enabling signal is present; f. monostable multivibrator delay means connected to be triggered by said current pulse and to trigger said bistable multivibrator means a predetermined time after the occurrence of said current pulse; and g. relay means connected to be operated by the outputs of said bistable multivibrator means.
Claim 15
Dependent Claim
176 words
Apparatus for producing a delayed operation of a relay in response to the appearance of one or more of a plurality of predetermined frequencies on a telephone line, comprising: a. a plurality of frequency signal recognition means each arranged to produce an output during the presence of one of said predetermined frequency signals on said line; b. level detection means responsive to the presence of one or more of said outputs to produce a fixed-level DC enabling signal; c. means for producing a current pulse at the beginning of said enabling signal; d. delay means for maintaining said enabling signal for a predetermined time following the total cessation of said outputs; e. bistable multivibrator means arranged to produce an output when triggered but only while said enabling signal is present; f. monostable multivibrator delay means connected to be triggered by said current pulse and to trigger said bistable multivibrator means a predetermined time after the occurrence of said current pulse; and g. relay means connected to be operated by the outputs of said bistable multivibrator means.
References Cited (Backward Citations)
US3156775A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-02 | 1975-02-01 | 1975-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-02 | 1979-02-01 | 1979-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-02 | 1983-02-01 | 1983-08-03 | $7700.00 | Window Closed / Lapsed |