Patent ID: 6842520

Claim:
A telephone comprising: an acoustic alarm; conversation members; first control means for the acoustic alarm; second control means for the conversation members; and first supply means and second supply means for absorbing energy from a telephone line, the first supply means and the second supply means supplying the first control means in a call condition and the second control means in a conversation condition, respectively, wherein: the first supply means further supply the second control means in the call condition; and the first supply means and the second supply means include a capacitor in common, for supplying the first control means in the call condition and for supplying the second control means in the conversation condition, the capacitor being connected to the first control means and to the second control means, wherein the first control means and the second control means are formed in a single control device, the control device having a reference terminal and a supply terminal, the capacitor having a first terminal and a second terminal connected, respectively, to the reference terminal and to the supply terminal of the control device, and in which the first supply means include a first input section and a first transistor and the second supply means include a second input section and a second transistor, each input section having a reference terminal, an input terminal, and an output terminal, the reference terminal and the output terminal of the input section being connectable to a telephone line, and each transistor having a first power terminal connected to the supply terminal of the corresponding input section, a control terminal connected to the output terminal of the corresponding input section, and a second power terminal connected to the second terminal of the capacitor, and wherein the second supply means comprise a further transistor having a first power terminal, a control terminal and a second power terminal, connected, respectively, to the supply terminal, to a further output terminal, and to the reference terminal of the second input section, and means for detecting a state of the second transistor and for activating the further transistor in dependence on the state detected.