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AssigneeOki Electric Industry Co., Ltd.
InventorsTokio Miyashita, Tokuo Nakamura, Toshihiko Kotaka
Estimating the term…
An off-hook signal and dial pulse generating circuit which has a smaller number of switching devices having a high withstand current characteristic and has a less surge voltage than up to now. A dial pulse circuit and a switch block circuit are connected in parallel with the output side of a full-wave rectifying circuit. The circuit comprises an impedance circuit and a first switch circuit to be turned on/off by a signal. The impedance circuit operates in a state where it has an inductance component in case that a signal synchronized with a signal is off and operates in a state where it has no inductance in case that the signal is on, and an electric current flowing therethrough is turned on/off by the first switch circuit. The circuit comprises a series circuit composed of second and third switch circuits. The second switch circuit is turned on/off in response to a signal synchronized with the signal (where this circuit is off when the signal is on). The third switch circuit is turned on/off in response to the signal.
An off-hook signal and dial pulse generating circuit which is provided between a telephone line and a communication terminal transformer, sends an off-hook signal or dial pulses to the office side through said telephone line in case that an off-hook signal or a first control signal for forming dial pulses is inputted, and forms a state where said communication terminal transformer is protected from input in case that a second control signal is inputted, said off-hook signal and dial pulse generating circuit comprising;
An off-hook signal and dial pulse generating circuit which is provided between a telephone line which has a constant-voltage constant-resistance system as its office-side power feeding system and has a line length where its line voltage can be kept at a certain value or higher and a communication terminal transformer, sends an off-hook signal or dial pulses to the office side through said telephone line in case that an off-hook signal or a first control signal for forming dial pulses is inputted, and forms a state where said communication terminal transformer is protected from input in case that a second control signal is inputted, said off-hook signal and dial pulse generating circuit comprising;
A method for driving an off-hook signal and dial pulse generating circuit, on the assumption that a signal for forming an off-hook signal or dial pulses is a first control signal and a signal for forming a state where a communication terminal transformer is protected from input is a second control signal, said method starting with a state where said circuit is in a waiting state and said first and second control signals are in an off state, and taking;
An off-hook signal and dial pulse generating circuit which is provided between a telephone line and a transformer part having a communication terminal transformer and a capacitor which is connected in series with this transformer and cuts off a direct current, and sends an off-hook signal or dial pulses to the office side through said telephone line in case that a first control signal for forming an off-hook signal or dial pulses is inputted, said off-hook signal and dial pulse generating circuit comprising;
Dependencies are inferred from the claim text.