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I'm using a sensor that has ethernet output. This new sensor is a replacement of yet another same sensor that seemed to have short-circuit like situation between its RX+/- pins.

After connecting the new sensor to my single board computer (SBC) there was no sign of activity/data and I checked the voltage on various pins and observed that the TX+/- pins appear to be having 0.8 Ohm resistance.

enter image description here ( source)

The circuit schematic of a magjack ethernet connector shows internal magnetic couplings and they might make the circuit appear like a short-circuit but be functionally normal. I'm confused if the RJ45 communication interface is intact or otherwise.

My question is: what is the expected resistance between TX+/- pins (and RX+/-) pins in a functional RJ45 socket?

vyi
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1 Answers1

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Most Ethernet transformers seem to be 0.9 ohms max so your 0.8 ohms is within specs.

The trasformer coil is basically a short circuit if you try to measure it with a multimeter.

Justme
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