Line repeater for telephone system using radio links
First Claim
1. In a telecommunication system wherein an exchange communicates with a plurality of local stations via respective radio links extending between a central terminal and a plurality of transceivers coupled by way of respective repeaters and line loops with said local stations, the latter having equipment operable by activating signals from said exchange,the improvement wherein each of said repeaters comprises:
- a constant-current generator provided with polarity-inverting means connected across a pair of conductors coupled to the associated line loop;
sensing means connected to said line loop for detecting the operational state of the associated local station and emitting a response signal upon ascertaining a predetermined change in said operational state;
logic circuitry with a first input connection from the associated transceiver and with a second input connection from said sensing means for emitting a switching signal under the control of an activating signal originating at said exchange and terminating said switching signal under the control of a response signal initiated by the associated local station; and
control means responsive to said switching signal inserted between said logic circuitry and said polarity-inverting means for reversing the current flow in said conductors to generate at least one binary pulse at said local station.
1 Assignment
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Accused Products
Abstract
A telephone exchange communicates with a number of scattered local stations via radio links extending from a central terminal to respective peripheral installations each comprising a radio transceiver coupled via a repeater to the line loop of an associated local station. The repeater includes a constant-current generator, combined with a polarity inverter, which is controlled via a logic network in response to signals from the exchange and from the local station (detected by a sensor in the line loop) to reverse the flow of direct current for the transmission of binary pulses to the local station. In the case of a private subscriber, these pulses may be an intermittent square wave generating a ringing signal; in the case of a public pay station they may constitute commands for the collection of tokens or coins.
14 Citations
11 Claims
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1. In a telecommunication system wherein an exchange communicates with a plurality of local stations via respective radio links extending between a central terminal and a plurality of transceivers coupled by way of respective repeaters and line loops with said local stations, the latter having equipment operable by activating signals from said exchange,
the improvement wherein each of said repeaters comprises: -
a constant-current generator provided with polarity-inverting means connected across a pair of conductors coupled to the associated line loop; sensing means connected to said line loop for detecting the operational state of the associated local station and emitting a response signal upon ascertaining a predetermined change in said operational state; logic circuitry with a first input connection from the associated transceiver and with a second input connection from said sensing means for emitting a switching signal under the control of an activating signal originating at said exchange and terminating said switching signal under the control of a response signal initiated by the associated local station; and control means responsive to said switching signal inserted between said logic circuitry and said polarity-inverting means for reversing the current flow in said conductors to generate at least one binary pulse at said local station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification