Termination circuit for decoupling unused wires on a network device's unshielded twisted pair (UTP) cable
AssigneeIntel Corporation
InventorStewart L. Gilbert
Life of this patent
Estimating the term…
Abstract
A termination circuit for unused wires in an unshielded twisted pair (UTP) cable in a local area network (LAN) device. In an eight wire UTP cable, four wires may be unused. The four unused wires are shorted to each other at a point of termination which is electrically connected to ground across a terminating resistive element having a resistance value in a range of about 0.36 to about 0.62 of a differential impedance of the UTP cable, e.g., 36 to 62 ohms for a UTP cable having a differential impedance of 100 ohms.
Claims22
Apparatus comprising:
- a transmission line having a differential impedance value and comprising a plurality of used wire pairs and a plurality of unused wire pairs, said plurality of unused wire pairs being electrically connected at a point of termination;
- and
- a resistive element having a first end electrically connected to the point of termination and a second end electrically connected to a grounding element, said resistive element having a resistance substantially matching a differential impedance between the plurality of used wire pairs land the plurality of unused wire pairs.
Apparatus for terminating unused wires in a transmission line, said apparatus comprising:
- a substrate;
- a connector having a first plurality of input ports adapted to receive a plurality of used wire pairs and a second plurality of input ports adapted to receive a plurality of unused wire pairs in a transmission line having a differential impedance and a plurality of output ports electrically connected to the second plurality of input ports, said plurality of output ports being electrically connected together at a terminal node;
- a grounding element adapted to be electrically connected to ground;
- a resistive element electrically connected to the terminal qnode at a first end and electrically connected to the grounding element at a second end, said resistive element having a resistance substantially matching a differential impedance between the plurality of used wire pairs and the plurality of unused wire pairs.
A method comprising:
- providing a transmission line having a differential impedance and comprising a plurality of used wire pairs and a plurality of unused pairs;
- electrically connecting the plurality of unused wire pairs at a terminal node;
- electrically connecting the plurality of used wire pairs at a testing node;
- determining a differential impedance between the plurality of used wire pairs and the plurality of unused wire pairs;
- disconnecting the plurality of used wire pairs from the testing node;
- and
- electrically connecting the terminal node to ground across a resistive element having a resistance substantially matching a differential impedance between the plurality of used wire pairs at the testing node and the plurality of unused wire pairs at the terminal node.
Dependencies are inferred from the claim text.