Switching between ethernet cables

Thread Starter

PeterT24

Joined Jan 29, 2020
2
Hi everyone,

I'm on a project where I have an arduino wich is connected to a router via an ethernet cable. But for redundancy reasons, I want to use a second (backup) cable either. So what I need is a circuit that switches between the main ethernet cable, and the bakup cable, when one of the arduino's pin is high or low. (The W5500 module is able to detect the link state, so that's how it will know when to switch to the other cable)

So I guess 8 relay would be the easiest way to do this, but they are loud and I don't want to use them if it's possible. There should be a way for this with some ic or something.

Made a little gif about it, where the perfboard is the thing i asked above.
Thanks for your answer / suggestion. Have a nice day.

ezgif.com-gif-maker73047ecfc4845aeb.gif
 

MisterBill2

Joined Jan 23, 2018
5,159
For a common ethernet connection only two of the pairs are used, so you can get away with a 4-pole relay. But what sort of situation requires a back-up cable? If just becoming disconnected is the only hazard, then you can just put them in parallel. If becoming short-circuited, either between conductors or to something else, then you will need to switch both ends.
 

pmd34

Joined Feb 22, 2014
503
The easiest solution would be to actually switch the lines between your arduino and W5500 .. and use 2 W5500 boards.
You might even get away with just switching the power off / on between the 2 boards, and having the connections in parallel.
Or failing that just switching the MISO and MOSI lines between the 2 boards.
You can buy ethernet switch ICs, but it would take some DIY pcbs etc, and your ethernet communication doesnt really need to be so high spec. as you are ultimately converting it to simple serial data anyhow.
 

MisterBill2

Joined Jan 23, 2018
5,159
I am still wondering about what environment would make immediate switching of an ethernet cable a requirement. Especially when it runs from such a tiny device as an arduino. Clearly there is a lot more involved than we have been told about.
 

Thread Starter

PeterT24

Joined Jan 29, 2020
2
So, the project is an ArtNet node. In the FOH there's the lightning console, along with a router. One cat5e cable goes to the stage. There's the ArtNet node. If the cable get damaged while the concert going, we can't control any of the stage lights.
So, if two cable goes to the FOH, and the node can automatically switch to the second cable, it's much more safe.
They use this technique with mixing consoles etc.
If you can suggest any other idea (IT wise, not arduino) in which I can use two cables to the FOH, and it's not including expensive gear for link aggregation or something, I look forward to your soution.

Thanks for the suggestions / infos. I attach an image of what am i talking about.
Untitled Diagram (2).png
 

djsfantasi

Joined Apr 11, 2010
6,116
I think that you’ve spec’ed yourself out of solution. Link Aggregation is the industry solution to this issue. If you go the DIY route, IMHO it’s going to fail on you, in situations where a single cable would work.

I’m prejudiced because I was part of a team that designed a HA e-Commerce web site. Every piece of gear had duplicate network connections on each LAN. Knowing the issues we faced, I wouldn’t trust a DIY aggregation scheme.
 

MisterBill2

Joined Jan 23, 2018
5,159
OK, now it makes some sense. If you can have an assistant in the area of that light controller panel then they could be trained to exchange a control cable. That could be simple and fast, but it does require an assistant. A second advantage is that it would be simple to have multiple spare cables.
 
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ci139

Joined Jul 11, 2016
1,171
the eternet link( controller)- s are generally capacitively decoupled so you likely can utilize quick enough pass-/transmission doors ?
Would you explain in detail
___________
while you can't

https://electronics.stackexchange.com/a/162750 (←← incase of short cables 1...2m the passgates might work otherwise there should be some over-voltage protection or relays as in the ←← post)
+ https://www.analog.com/media/en/technical-documentation/application-notes/EE-269.pdf (Fig.14) in detail http://ww1.microchip.com/downloads/en/DeviceDoc/Fast 100Mbps Ethernet PICtail Plus Rev 1 Schematic.pdf (pg.2)
the other Zebras http://www.inelco.de/intrajack.php
 
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MisterBill2

Joined Jan 23, 2018
5,159
Ok, if a switching circuit would not be reliable enough, and indeed an avearge homebrew system may not be durable and robust enough, consider a pair of heavy-duty cables. Still cat5, or whatever grade your application needs, but the material with the heavier insulation and the much thicker jacket.And no coupling connectors, just one run of cable from end to end. One more thought is that there must indeed be some sort of stage hand around during the performance. If that person is able to learn how to swap cables, then changing over manually could be a valid approach.
 

Sensacell

Joined Jun 19, 2012
2,561
Nobody switches ethernet wiring, it's the wrong tech for the wrong idea.

Use two of the W5500 boards.

Ethernet cables need to be a precisely controlled impedance, any relays, gates or other stuff you introduce will open a nasty can of worms.
 

MisterBill2

Joined Jan 23, 2018
5,159
Nobody switches ethernet wiring, it's the wrong tech for the wrong idea.

Use two of the W5500 boards.

Ethernet cables need to be a precisely controlled impedance, any relays, gates or other stuff you introduce will open a nasty can of worms.
The higher the speed the more critical controlling the impedance and avoiding reflections becomes. That is indeed the challenge of ethernet wiring. That is why I suggested simply having an assistant able to switch over in case of a failure.
BUT really, a properly installed cable with adequate protection should be reliable. And a FULLY REDUNDANT link arrangement would be the best choice if cost is not the primary consideration. That would include all of the interface hardware.
And iif reliability is really important I would include a backup arduino since that is probably the least reliable part of the whole setup, and also the cheapest to duplicate.
 
This is an old post, sort of and I hope the TS came up with a solution.

My comments are two-fold

1. I have a commercial A/B switch I bought used. It claimed it was tested at 1000bT speeds. Internally, it used twisted wires direct to the jack. No PCB traces. Actually, I'm not even sure they were twisted. This one can be manually or RS232 controlled. It is 3 independent A/B switches.

2. If you built such a box or even didn't build one, you might be better off with the industrial circular connectors for the cables that are moved frequently.

I never got one of those ROUND TUITS for my application which is to swap two DSL modems. One configured for bridge mode and the other for direct connect.

In fact, I never put together what I used to have either. Power the DSL modem from a UPS and Power Over Ethernet. The other thing I need is to connect the UPS to my RAID server.
 

djsfantasi

Joined Apr 11, 2010
6,116
It’s been long enough for me to remember the nitty gritty technical details. But I’m sure what @KeepItSimpleStupid describes doesn’t need a hardware switch. Either the host has two Ethernet connections, one to each DSL modem and they are configured in a failover configuration. Or a single Ethernet connection is configured with two connections, a primary and alternate.

I ran into almost every redundant Ethernet configuration possible and with the proper configuration could connect via either path.

If dual DSL routers in a redundant configuration rather than a switched configuration is wanted, configure them as redundant and only turn on the desired router.
 
In my case, it would not be for redundancy. My modem is mounted in the ceiling about 5' from the NID outside like it should be, close to the NID. The POTS wiring is a hodge-podge of quad cable and basically two major connection points, but jacks could have 4-prong and modular nearby. There is a splitter in the NID. CAT5 cable from the NID to a small punch-down.

That splits to an old carbon protector and screw block, the telco side of the splitter and a DSL jack. There are about 12 phone locations in the house.
Most of the ringers are disconnected. Now, phone is mostly 4 handhelds with a base answering machine. The base is on a UPS. A baby monitor repeats the ringing signal of the least unused phone to two locations. The laundry room and my bedroom. I can tell by the ring if it's an outside call or intercom. The intercom function is used a lot as a "nurse call" system. One of the parental units, I take outside in the yard. I can;t hear my cell ring most of the time.

There is a LED mounted above the TV that indicates whether the phone is off-hook or ringing. Basically a stock product from Viking. The LED, resistor and regulated power supply are upgraded.

I want to add some large LEDs in my bedroom that would indicate talking. More specifically, I want off hook and "not talking for x time". i want to indicate the baby monitor going off.

there is a CAT4 or CAT5 (RJ11) to the modem. A rare cable to find. The output of the modem goes to the ceiling in the middle of the basement where the network stuff is and a RAID server.

When I was trouble-shooting a Verizon connection, I was basically swap modems. e.g. DSL inputs and WAN outputs then connect my laptop direct to the modem. In bridge mode I can't see anything at all even link speed. Verizon "accidently" lowered my link speed by a factor of 2 and I plugged my laptop into the router in the ceiling and I ended up accelerating my laptop to 9.8m/s^2 from about 3'. Screen cracked and hard drive was damaged beyond repair.

I at least mounted a ethernet outlet near the router and near a ersatz table (the clothes washer) so I can't pull the cable and drag the laptop to the floor. The hard drive died months later and was not salvageable. Hence the RAID server.

Some device doesn't reset properly after a power glitch, so it's either a power recycle or UPS. I had a UPS until it died.

There is a little plastic insert that can go into a 8C8P connector and turn it into a 6P6C connection, so I would use that for the DSL switch side.

I just want an easy way to swap modems for testing purposes. the minimalist method is to plug the modem into the NID outside and I've had to do that for repair.
 
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