Ethernet automatic adapter interface card
AssigneeFarallon Computing, Inc.
InventorJohn R. Marum
Life of this patent
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Abstract
An Ethernet adapter card for automatically switching a workstation into a network is provided. The adapter card utilizes a current circuit to sense current drawn by an external communications network and a circuit for automatically switching between a card-mounted internal transceiver and the network's external transceiver whenever the external network is coupled to the workstation via an AUI port. The adapter card provides for default selection of the internal transceiver when the external communication network is disconnected from the workstation AUI port.
Claims4
A current sensing automatic switching network comprising:
- an attachment unit interface port having a power supply line, first and second transmit lines, first and second data receive lines, and first and second collision detect lines;
- an internal transceiver having input and output signal terminals comprising first and second transmit terminals, first and second data receive terminals, and first and second collision detect terminals, said internal transceiver characterized in that it tristates said input and output signal terminals when it is powered down, said internal transceiver having a power terminal at which power may be applied;
- a plurality of DC isolating means each individually coupling one of said transmit lines, data receive lines, and collision detect lines of said attachment unit interface port to a respective one of said transmit terminals, data receive terminals, and collision detect terminals of said internal transceiver;
- and
- a current sensing circuit coupled to said power supply line of said attachment unit interface port and coupled to said power terminal of said internal transceiver for powering down said internal transceiver when current is drawn through said power supply line of said attachment unit interface port.
A circuit comprising:
- an attachment port at which an external transceiver may be connected, said attachment port having a power supply line and input and output signal lines;
- an internal transceiver having input and output signal terminals, said internal transceiver being characterized in that it tristates said input and output signal terminals when it is powered down, said internal transceiver having a power terminal at which power may be applied;
- a plurality of DC isolating means each individually coupling one of said input and output signal lines of said attachment port to a respective one of said input and output signal terminals of said internal transceiver;
- and
- a current sensing circuit coupled to said power supply line of said attachment port and coupled to said power terminal of said internal transceiver for powering down said internal transceiver when current is drawn through said power supply line of said attachment port.
Dependencies are inferred from the claim text.