Ethernet hub?

[lazarus78]

I have a situation where it would be VERY helpful if I could use my laptop alongside a Raspberry that is in some location. The issue I have is, WiFi is not available, and there is only 1 Ethernet cable (For the Pi). So I thought a small Ethernet hub would be perfect for gaining a temporary port so I can wire in and work on the Raspberry and view the display. In truth, I am not needing to connect to the Raspberry itself, but rather another Linux computer elsewhere that is providing files for the Raspberry to display. I need to adjust them for formatting purposes and whatnot.

Is it possible to make a simple passive hub? I can't find much information on passive hubs, let alone active hubs. I don't need to worry about attenuation or collisions as I am not trying to extend an Ethernet line and there will only be 2 devices on this one cable.

[DougieLawson]

Buy one. They're cheap and it will work out of the box.
http://www.amazon.co.uk/TP-Link-TL-SF10 ... B000FNFSPY

[lazarus78]

I'm looking specifically for a passive hub, unless there is such a thing as a passive switch, but doubtful. I was hoping to just "tap" in to an existing line temporarily with as few wires involved as possible.

[DougieLawson]

That's precisely what that TP-Link box does.

[lazarus78]

That's precisely what that TP-Link box does.

So its 100% passive? No external power necessary? The power port in the pictures confused me.

Guess that solves my problem then. Thanks for the help.

[KeithSloan]

I think you will find it needs power as the amazon page says
Box Contains
5-Port 10/100Mbps Desktop Switch
Power Adapter
User Guide

[DougieLawson]

That's precisely what that TP-Link box does.

So its 100% passive? No external power necessary? The power port in the pictures confused me.

Guess that solves my problem then. Thanks for the help.

Your definition of "passive" and mine differ. Passive doesn't mean unpowered, passive means uncontrolled. I don't think you'll find any kind of ethernet equipment that doesn't need a power supply.

[lazarus78]

Your definition of "passive" and mine differ. Passive doesn't mean unpowered, passive means uncontrolled. I don't think you'll find any kind of ethernet equipment that doesn't need a power supply.

I've learned passive to mean no added power, IE a passive USB hub vs an active hub which required added power, which is in line with the engineering definition of passivity.

But anyhoo, semantics.

My question seems to have been answered.

[pksato]

Hi, yes is possible to build a passive hub.
http://www.zen22142.zen.co.uk/Circuits/ ... ethhub.htm

But, I don't know if really work.

And, probable, you can find a used 8 port switch with less that cost of connectors and diodes.

[plugwash]

The twisted pair ethernet standards do not make any allowances for passive hubs. The hack that pksato linked may just about work for 10baseT, I would be very surprised if it worked for 100base-T

You can get ethernet switches that are powered off USB which at least saves the need for the mains adapor

https://www.blackbox.co.uk/gb-gb/si/150 ... h/V1.S1.O4

[n3tm4n]

I've played with the cabled box before, but it can cause havoc with auto negotiation as a series of Fast Link Pulse which would be very confusing if multiple things responded to. The upstream port is likely to go into some error state.

I would go for a powered hub, bear in mind that if there are any mac-address filters or limit on the upstream device you may find that one device works and additional ones dont, or worse still none work.

If you do have an environment with mac filters or security, then you may be better with a cable network wifi box running stock or DD-WRT and use it as the connection point.

I'm a big fan of the raspberry-PI, but sometimes other things do the job easier. My old faithful linksys router is a constant travelling companion when on the road for just such occassions. Connecting to an upstream wifi and providing 4 eth ports, or connecting to an upstream ethernet, and providing 4 eth ports and a wifi.

If a mod ever comes out to get 4 ethernet ports working on a Pi I will be first in the queue.

HTH.
Jon.