Abstract: A hook flash actuated telephone control device that is connected into a subscriber's telephone line to permit a user to place an existing call on hold by selectively activating the hook switch of his telephone according to a particular sequence. The control device includes a comparator which senses the line voltage and produces an output signal, the level of which is dependent upon whether or not the telephone handset is in an on-hook or off-hook condition. First timing and logic means are interconnected so as to be triggered by the output signal of the comparator. If the telephone handset is in an off-hook condition and the hook switch flash signal sequence is completed within a first particular predetermined time, a corresponding signal is generated to energize a hold circuit, whereby to place the telephone circuits in a hold condition. Audio signal generating means are also energized in order to provide the user with a tone to indicate that the telephone circuits are rendered in a hold condition.

Abstract: In a first preferred embodiment of the invention, a clip-on switching device is disclosed to prevent the placing of unauthorized outgoing calls from a (Touch Tone) telephone and/or to selectively switch an incoming call to an accessory (extension) telephone circuit. The switching device includes a housing which is particularly shaped to conform to the contour of the telephone cradle so as to be releasably connected therewithin. Positioned within the housing is a card having a control circuit thereon for selectively controlling the telephone circuitry. A unique spring-biased light emitting diode push-button switch is associated with the instant switching device, whereby to provide a visible signal, so as to indicate the operation of the telephone control circuit.

Abstract: A housing for containing accessory controls for an associated telephone mountable within the cradle of the telephone which conforms with the contour of the telephone and has positioned within the housing a card for selectively controlling the circuitry of the telephone.