Will a webcam work with a 50m cord?

Question

Computer networks

If you buy a cheap usb webcam ($3-5) and a USB-RJ adapter ($2),
and hang this on a 50-meter ethernet cable.
Would such a design work?
It is especially interesting if there are two adapters at the second end: RJ->USB->miniUSB to see the image in the phone.
And will it be possible to use two wires in the cable for powering 12V? (You also need a flashlight on the other end).

Answer 1

Here the person writes that yes, it will work. But it must be assumed that not every device needs to be tried.
The principle of the "active USB extender" is that 12 (well, or even more) is made at the supply end of 5 volts, these 12 are transmitted over a long cable, a voltage drop occurs on the cable due to its length. But at the receiving end, from what is left, the stabilizer still makes the necessary 5 volts. And the digital signal is apparently buffered to eliminate the effect of the increased cable length. Personally, I happened to lengthen the wire from a regular webcam (though only up to a length of 10 meters) without any buffering and other electronic stuffing, and everything worked fine. I did this - I put one twisted pair for data transmission (lines D + and D-), soldered the other three in parallel and put 5 volts on power. The drawdown was 0.2 volts, i.e. did not exceed the allowable 5%.
If you also need to power a flashlight at the receiving end, see the description of the active extension cord used, i.e. how much current it can provide. If it does not fit, the flashlight will not have to be added.

Answer 2

It depends on what kind of twisted pair, the copper wire holds 12 volts 5A up to 50 meters no more. Copper holds about 70-100 meters. Everything has been tested experimentally.

Answer 3

no. the maximum length of one segment according to the standard is 5 m. in fact, it can be a little more if you are very lucky with the cable and equipment - 2 times. you can set up to four hubs to increase the number of segments to five. but ... this is all shamanism, which does not at all guarantee that in the end the scheme will work, and the cherished fifty meters cannot be achieved in this way anyway.
you can try https://www.google.com/search?q=usb+ethernet+extender .