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1 vote

Jumper on 100 Mbps Ethernet

If they are in pairs in series with the line, then no unbalanced length is added, only a little uncoupled length. Crosstalk, CMRR, etc. may be impaired slightly, depending on layout. Even gig isn't ...
Tim Williams's user avatar
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1 vote

10/100 Ethernet PHY: What is this capacitor for?

It provides a local ground reference for the resistors, which should be placed near the PHY chip. It could also be tied to +1.8V (or whatever VCC is; usually 3.3V), but the capacitor is sufficient as ...
Tim Williams's user avatar
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1 vote

MII to SGMII to connect ETH Switch is it possible?

MAC stands for Media Access Control and it is the controller that allows a device to interact with a physical layer ethernet device (PHY) STM32F4 datasheet You need to match the MII to something that ...
Voltage Spike's user avatar
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0 votes

Measuring Ethernet Impedance

I suspect there is a signal integrity issue that is causing the ethernet to work intermittently, but how do I go about proving it? First and foremost - there is not differential pair or impedance for ...
Voltage Spike's user avatar
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4 votes

Is there a way to non-destructively test whether an Ethernet cable is pure copper or copper-clad aluminum (CCA)?

Measure the resistance as suggested by @user180479. Aluminum has a resistivity about 1.6 times higher than copper. Weigh the cable an see how it compares to solid copper cable. You should get a good ...
qrk's user avatar
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6 votes

Is there a way to non-destructively test whether an Ethernet cable is pure copper or copper-clad aluminum (CCA)?

Since the resistance of copper is different than the resistance of aluminium, you can measure the electrical resistance of the line and see if it matches the expected value for the gauge the vendor is ...
user1850479's user avatar
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9 votes
Accepted

Can a capacitor be used to close path between center-tap and shield instead of Bob-Smith (capacitor+resistor)?

Why not both? You can series a resistor and capacitor just fine. The capacitor should be some 10s of nF, I suppose, so that its peak (AC) voltage during ESD is small (the 1nF still handles most of it)...
Tim Williams's user avatar
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