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RE: Spare pair termination.

Title: RE: Spare pair termination.

Just to remind everyone of existing schematic implementations; look at:

This shows existing practices.

The common mode termination cap is usually around 1000pF rather than 0.1uF,
since it needs to be a 2kV cap in order to pass Hipot tests.
So common mode termination is AC coupled not DC coupled.

Due to Hipot, each wire of the RJ-45 must not be tied to ground.
Hipot is: tie all 8 pins together, ramp to 2250VDC for 60 seconds,
then ramp to 500 VDC, the leakage must be higher than 2 meg.

I hope this helps,
- Rick