Ethernet to USB adapter?

[SSThing]

Is there an adapter available that will plug into the Ethernet socket and convert to a USB so that I can use the power from the Ethernet socket to operate a usb fan?
Hopefully I have made sense?

[tmihai20]

It is the first time I ever hear about it. Why would you do that? It is a lot easier to use a powered USB hub in case you do not have enough free USB ports.

[stl]

Is there an adapter available that will plug into the Ethernet socket and convert to a USB so that I can use the power from the Ethernet socket to operate a usb fan?
Hopefully I have made sense?

Ethernet port would have to be POE compatible but voltages are usually much higher than 5V
https://en.wikipedia.org/wiki/Power_over_Ethernet

[SSThing]

It is the first time I ever hear about it. Why would you do that? It is a lot easier to use a powered USB hub in case you do not have enough free USB ports.

My home AV amp needs additional cooling at times and only has one usb port on the front and I do not want anything plugged in there because it would mean the front panel being open all the time. It has a poe socket at the back so I am hoping to plug something into there so it only operates when the amp is on.

[akurej]

So this does not involve HiMedia Player at all! :-)

I guess you just need an active POE splitter which outputs 5V to connect to your USB fan.
https://goo.gl/8xdRse

[LeoeL]

The power splitter splits if there is something to split. 
In your case LAN port doesn't transport any "power" so it's useless.
Why not a simple 230V USB adapter?

[akurej]

It has a poe socket at the back so I am hoping to plug something into there so it only operates when the amp is on.

Did you confirm that this is POE socket? Is this mentioned in the manual? What's the AVR model no?

The power splitter splits if there is something to split. 
In your case LAN port doesn't transport any "power" so it's useless.
Why not a simple 230V USB adapter?

He did mention POE socket. So let him confirm 
Adapter is an option but I think he wants the fan to operate automatically whenever AVR is powered on.
And whenever AVR is shut down the fan also stops.

[stl]

It is the first time I ever hear about it. Why would you do that? It is a lot easier to use a powered USB hub in case you do not have enough free USB ports.

My home AV amp needs additional cooling at times and only has one usb port on the front and I do not want anything plugged in there because it would mean the front panel being open all the time. It has a poe socket at the back so I am hoping to plug something into there so it only operates when the amp is on.

I don't think you'll find an adapter. Your best option is to cut a Ethernet cable, measure the supplied voltage on the wires and connect a fan that works with that voltage or use a step down DC converter. If you're not conformable doing this leave it alone, you might damage something.
You can also use the amp power supply, probably you have 5V and 12V there.

[LeoeL]

I don't think there is an AV receiver with POE LAN port.

[SSThing]

http://www.eu.onkyo.com/assets/2/7/0/0/8/TX-NR3030__B__Rear_N9999x9999.png.jpg

For some reason this was designed with only one usb which is on the front under the facia plate. Not wanting to have additional power supplies and cables trailing across my AV kit I was hoping for a simple solution where the fan was operating when the amp was on and off when it is off.
The unit is a couple of years out of warranty so I may just open it up, locate the usb header on the control board and attach a new usb port routed out through the back somehow as I have only ever used the front usb for firmware updates (which have stopped now).

[akurej]

So this has the normal Ethernet port. There will be no power available on this port.

The USB port on the AVR may output power even when the AVR is on standby. 
So this means your fan may always be on.  So please check by connecting your USB fan or mobile when AVR is on standby.

Best maybe to get separate adapter for the fan.  You try could using a remote plug for adapter and programme it to your AVR power button.
So each time you press the remote power button the fan will come on along with the AVR, and switch off when you press again.