USB Powered Network Switch

Dygear · October 2, 2019

I'm looking for a USB powered Network Switch. Currently I'm using the Hak5 Micro Ethernet Switch and it's great. But there are some draw backs, mostly in the fact that it's only 10/100Mbps and not GbE.

I was wondering if anyone out there had any ideas if a USB Powered GbE switch exists? What I'm thinking of doing, as I've found none that accept a native USB connection yet, is simply using a USB to Barrel Jack Adapter and connecting that to a D-Link's DGS-105 5 Port Gigabit Switch. This takes 5Vs @ 1A so it's out of spec for a USB2 port (500mA), but very close to a USB3 port (900mA).

mariushm · October 2, 2019

Yes, it will work.

This model will probably be slightly better:

16$ TRENDnet TEG-S50g : https://www.amazon.com/TRENDnet-Unmanaged-GREENnet-Switching-Protection/dp/B001QUA6R0/ or https://www.newegg.com/p/N82E16833156250

product page: https://www.trendnet.com/products/unmanaged-switch/5-port-gigabit-greennet-switch-v5

TRENDnet is a decent manufacturer, it's not noname, you can buy it without worries.

It claims it needs only 2.75w max to operate, that's 0.55A on 5v... an USB 3 port will do 0.9A. With only 2-3 network cables plugged in, the average power consumption will be lower.

The switch uses a DC-DC converter to convert 5v to something like 3.3v for the switch IC .. nothing inside works directly at 5v, so no need to worry about usb voltage drop or other stuff like that.

Also usb ports in the back of your computer are usually protected with a 2A fuse (for example, 4 usb 2.0 ports or 2 usb 3.0 ports share a 2A reset-able fuse) so if not all 2 or 4 ports in the group are used to the maximum, the computer is none the wiser and it can give up to around 2a

The switches come with a 5v 1A adapter for two reasons:

* because 5v 1A wallwarts are mass produced and it's not worth for them to save 1-2 cents by ordering let's say 0.75A wallwarts - they buy tens of thousands of wallwarts and reuse these for multiple models of switches. They only make the switches, not the wallwarts.

* because the wire between wallwart and switch is long, there can be some voltage drop on it so it's a good idea to have some margin.. for ex. let's say the dc-dc converter needs 3w to produce 2.75w. With 5v input, that's gonna be 0.6A (3w/5v) but if the wires are thin you may get only 4.75v at the switch dc jack, so the dc-dc converter now needs 3w/4.75v =~0.65A . You won't have this problem with short usb cable.

edit: i forgot an important third reason : it's better to have the power supply run at 50-75% of its rating for most of its life and heat less and have fewer failures (which would raise warranty claims and damage the brand name) instead of running the power supply at 90-100% of its rating all the time. With USB cable you won't have this problem.