Dataset powered by control and data signals from data terminal
First Claim
1. Data communication apparatus of the type comprising a data terminal apparatus for developing electrical data signals and a dataset apparatus for modifying and controlling the data signals prior to transmission along transmission lines, said data terminal apparatus including means for developing said electrical data signals and means for developing control signals and separate terminal connectors at which said data signals and control signals are presented, said dataset apparatus including separate terminal connectors for receiving said separate data signals and control signals and power supply means connected to a plurality of said terminal connectors for receiving said data signals and control signals so as to extract, solely from said control and data signals, power supply voltage for said dataset apparatus.
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Accused Products
Abstract
A dataset apparatus is powered by voltages extracted from electrical signals passing between the data terminal apparatus and the dataset by circuits comprising a capacitor and diode combination. The transmitter of the dataset includes capacitance isolation of the signal from the transmission lines by applying an oscillated voltage and an inverted oscillated voltage dependent upon the signal to capacitors in a first circuit to charge the capacitors through a diode whereby the oscillating voltage causes the capacitors to discharge through a second path formed by further diodes to charge a pair of capacitors coupled across the transmission lines. A second circuit of similar impedance to the first charges the capacitors to the opposite polarity. The arrangement can handle high common mode voltages on the transmission lines. The receiver of the dataset includes a doubly balanced resistance bridge network connecting the transmission lines to a differential amplifier, the circuit being balanced such that signals from the transmitter are not applied to the amplifier and also common mode signals are not applied to the amplifer.
52 Citations
11 Claims
- 1. Data communication apparatus of the type comprising a data terminal apparatus for developing electrical data signals and a dataset apparatus for modifying and controlling the data signals prior to transmission along transmission lines, said data terminal apparatus including means for developing said electrical data signals and means for developing control signals and separate terminal connectors at which said data signals and control signals are presented, said dataset apparatus including separate terminal connectors for receiving said separate data signals and control signals and power supply means connected to a plurality of said terminal connectors for receiving said data signals and control signals so as to extract, solely from said control and data signals, power supply voltage for said dataset apparatus.
- 6. Dataset apparatus comprising first terminal means including a plurality of separate terminal connectors for attachment to data terminal apparatus for receiving therefrom and supplying thereto at respective ones of said separate terminal connectors electrical data signals and electrical control signals, second terminal means for connection to transmission lines, means for modifying and controlling electrical data signals emitted from said terminal apparatus prior to transmission on said transmission lines as transmitted data signals and electrical data signals received from said transmission lines prior to transmission to said terminal apparatus as received data signals, and power supply means for said modifying means, said power supply means being connected to a plurality of said terminal connectors for receiving said control and data signals from said terminal apparatus for extracting voltage solely from said control and data signals whereby to provide power for generating said transmitted data signals for said transmission lines and for generating said received signals for said data terminal.
Specification