US3973200A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for acknowledging calls in a system for wireless staff locators
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1975-01-23
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Granted: 1976-08-03
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Expires: 1995-01-23
Abstract
Abstract In a system for wireless staff location where non-coded acknowledgement signals are transmitted from a called staff locator to identify the staff locator from which the acknowledgement signal is sent which is characterized by the fact that the acknowledgement signal is allotted to the staff locator whose coded call signal was last transmitted.
Inventors
- 👤 Dag E:son Akerberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:20
CPC Classifications
H; H04; H04W; H04W88/00; H04W88/18; H04W88/185; G; G08; G08B; G08B3/00; G08B3/10; G08B3/1008; G08B3/1016; G08B3/1083
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
192 words
In a system having a central station including means for repeatedly and cyclically transmitting coded call signals and a number of substations each including means for selectively receiving the coded call signals, an alarm emitter, a manually actuated acknowledgement means and an acknowledgement transmitter for delivering an acknowledgement signal signifying that a call signal directed to the substation in question has been received and recognized, and its alarm emitter has emitted an alarm signal, a method for identifying at the central station which substation has transmitted the acknowledgement signal received at the central station comprising the steps of at a substation, on condition that its acknowledgement means has been manually actuated after the alarm signal has been recognized, transmitting a short acknowledgement signal which is the same for all substations immediately after the call signal occurring after manual actuation of the acknowledgement means has been received and recognized as being directed to the substation, keeping the central station ready for a short time interval after the transmission of a call signal to receive an acknowledgement signal, and allotting the received acknowledgement signal to the substation whose coded call signal was last transmitted.
Claim 2
Dependent Claim
192 words
In a system having a central station including means for repeatedly and cyclically transmitting coded call signals and a number of substations each including means for selectively receiving the coded call signals, an alarm emitter, a manually actuated acknowledgement means and an acknowledgement transmitter for delivering an acknowledgement signal signifying that a call signal directed to the substation in question has been received and recognized, and its alarm emitter has emitted an alarm signal, a method for identifying at the central station which substation has transmitted the acknowledgement signal received at the central station comprising the steps of at a substation, on condition that its acknowledgement means has been manually actuated after the alarm signal has been recognized, transmitting a short acknowledgement signal which is the same for all substations immediately after the call signal occurring after manual actuation of the acknowledgement means has been received and recognized as being directed to the substation, keeping the central station ready for a short time interval after the transmission of a call signal to receive an acknowledgement signal, and allotting the received acknowledgement signal to the substation whose coded call signal was last transmitted.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein the call signal and the acknowledgement signal are transmitted with different carrier frequencies.
Claim 4
Dependent Claim
37 words
The method of claim 1 wherein the acknowledgement signal produced by the acknowledgement transmitter of the substation is a carrier frequency signal modulated with a modulating signal having a frequency which is characteristic for each individual system.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-03 | 1980-02-02 | 1980-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-03 | 1984-02-02 | 1984-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-03 | 1988-02-02 | 1988-08-03 | $7700.00 | Window Closed / Lapsed |