Telephone security device
First Claim
1. A telephone security device for preventing unauthorized use of a telephone subscriber'"'"'s set, the device comprising:
- inhibit means for connection to the called number selecting means of the subscriber'"'"'s set for at least partly inhibiting the operation of said selecting means;
code signal recognition logic means which has an input for receiving code signals and which is operable for responding to the reception thereby of first and second predetermined multiple-digit numerical code signals to produce corresponding first and second mode output signals, andmode register means which has two stable mode states, which is connected to said code signal recognition means and said inhibit means, and which is operable when it is in one of said two states to respond to the reception from the code signal recognition means of said first mode output signal to enter the other of said two states and to remain in the said other state even following disconnection of a subsequently made telephone call and when it is in said other state to respond to the reception of said second mode output signal from the code signal recognition means to enter said one state, the mode register means being further operable to control said inhibit means so that, for as long as the mode register means is in said one of said two states, the inhibit means prevents any successful attempt to use the said called number selecting means to make outgoing calls to at least some destination telephone numbers and, for as long as the mode register means is in said other state, the inhibit means is inoperative and hence allows any number of outgoing calls to be made normally.
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Accused Products
Abstract
A telephone security device for preventing unauthorized use of a telephone subscriber'"'"'s set comprises an inhibit device for rendering at least partly inoperative the called number selecting means of the set, and a code responsive control means for controlling the inhibit device in dependence upon predetermined code signals applied thereto by the authorized user(s) via the called number selecting means or via a separate keyboard. An emergency service number is obtainable at any time even when other calls are inhibited. Additional predetermined code signals are required to return the inhibit device to an inhibit mode.
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Citations
10 Claims
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1. A telephone security device for preventing unauthorized use of a telephone subscriber'"'"'s set, the device comprising:
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inhibit means for connection to the called number selecting means of the subscriber'"'"'s set for at least partly inhibiting the operation of said selecting means; code signal recognition logic means which has an input for receiving code signals and which is operable for responding to the reception thereby of first and second predetermined multiple-digit numerical code signals to produce corresponding first and second mode output signals, and mode register means which has two stable mode states, which is connected to said code signal recognition means and said inhibit means, and which is operable when it is in one of said two states to respond to the reception from the code signal recognition means of said first mode output signal to enter the other of said two states and to remain in the said other state even following disconnection of a subsequently made telephone call and when it is in said other state to respond to the reception of said second mode output signal from the code signal recognition means to enter said one state, the mode register means being further operable to control said inhibit means so that, for as long as the mode register means is in said one of said two states, the inhibit means prevents any successful attempt to use the said called number selecting means to make outgoing calls to at least some destination telephone numbers and, for as long as the mode register means is in said other state, the inhibit means is inoperative and hence allows any number of outgoing calls to be made normally. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification