Patent ID: 8260563

Claim:
A system operating in a process control environment, the system comprising: a field device to perform a process control function in the process control environment; a remote device disposed away from the field device to perform an auxiliary function associated with the process control function of the field device; a first wired communication link communicatively coupled to the field device and to the remote device to support data communication between the field device and the remote device; and a common-mode noise reduction circuit coupled to the field device and to the wired communication link to reduce common-mode noise generated in the first wired communication link; wherein the first wired communication link includes a plurality of electrical wires, and wherein each of the plurality of electrical wires connects to the field device at a respective one of a plurality of inputs; wherein a first one of the plurality of electrical wires is associated with a first impedance at a first one of the plurality of inputs and a second one of the plurality of electrical wires is associated with a second impedance at a second one of the plurality of inputs, wherein the first impedance is substantially different from the second impedance; and wherein the common-mode noise reduction circuit matches the first impedance to the second impedance so that the common-mode noise generates an equal voltage on the first one of the plurality of electrical wires and the second one of the plurality of electrical wires.