In article , praveen wrote: :I am want know the frequency of the ethernet data so that i can decide :on the value of the inductor through which i can feed DC power. :I have heard the ethernet can range from DC to 10 Mhz (10TBase), in :this case i cannot feed power on ethernet.
I don't know about DC, and I don't recall the details about 10BaseT, but at the higher bit rates, the frequency is not just
1/(megabits per second): instead, they use a slower carrier and more bits per symbol. Some error correction is used, so the raw number of data points sampled exceeds the nominal bandwidth.
10/100/1000 BaseT are all async, so when there is no data going through, there are no pulses on the line. I never looked deeply enough to find out whether it uses a DC carrier or if the line floats free.
If you are using 10BaseT, then several of the wires on a typical Cat5 8-wire RJ45 setup are not used at all (not even as grounds): if you need to carry power, could you perhaps use those wires? This might not help if you are running Cat3 instead of Cat5.