I made something, it works but it's probably not good

Hello everyone

The following situation: for a customer we needed a LAN connection relatively far away from the office (several floors below, according to my measuring device, about 40 meters of cable). Only a very small bandwidth is required (few Kbit/s, for a door control). The UP is right next to this door and where we need the connection. Theoretically, just pull a LAN cable through the empty pipe where the U72 goes through and you’re good. The problem is that it has a loop box in between, we also know where it is, but it was more or less bricked over it, exposing it would be a huge deal

Between the office and the UP there is a 5*4*0.5mm U72, only a few of which are in use for the 350/100 gFast Anschluss. Then I had the “great idea” to use 4 of the other wires in the U72 for a 10/100 LAN connection. This works perfectly, but the bandwidth of the Internet Anschluss is halved as soon as I connect something to the other end, to 180/100 Mbit/s (due to crosstalk, even though I specifically used all 4 wires in another 1*4 part of the U72 because I thought they were twisted together four at a time, but the twist is probably not tight enough)

However, if I set the link speed to 10 Mbit/s FDX on the switch at the other end then it works fine and no longer disturbs the gFast line. This makes sense because 10 Mbit/s Ethernet uses frequencies well below gFast

Do you know any better solutions for this situation? A 4G router just for the door is not an option (too little cell phone reception), ordering a second internet subscription would definitely be an idea (and installing the router directly in the upstairs) but the customer actually wants to avoid that because of the costs. WiFi is not possible due to the distance. Cable somehow surface-mounted or outside the building would be possible but would take hours of effort

One idea I had was VDSL2 media converters, but chasing this signal through the same U72 as the gFast line doesn’t seem much better to me than the “tinkering” now

The Ethernet connection itself is tip-top stable, even at 100 Mbit/s

The customer and I are aware that this solution is a real tinkerer and if I were to come across it somewhere my first thought would be “what idiot did that?”

What do you think about that?

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@NilsL wrote:

[…] The customer and I are aware that this solution is a real tinkerer and if I were to come across it somewhere my first thought would be “what idiot did that?”

What do you think about that?

I mean about the same thing as you do 😂

But what else you could do… difficult. A two-wire intercom system might be a bit more elegant, or if it’s just a door magnet, simply attracting it via two wires. Or doing something with RS232/RS422/RS485.

No matter how you twist and turn it, if you want it to be really clean and professional, there is probably no way around a separately laid cable.

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Have you tried turning it off and on again?

@PowerMac That was also a thought, the problem is that the door control has an RFID reader on the outside and it is connected to the control with an internal bus via a LAN cable (simply 8 wires) at the end tied together. You also need 2 contacts for the opening impulse. The RFID reader probably uses an RS485 bus, at least I read something about it in the instructions

However, I don’t know how much better it would be if I ran everything through the U72 (the number of cables would make it work and if it’s RS485, the longer shouldn’t be a problem). However, the full current flows from the electric opener through the opener relay in the control. I don’t trust the U72 to do that, so I would have to tinker with a relay

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@NilsL

The question may also be whether this location will be developed with FTTH in the near future.

If this were the case, the issue of the “bricked up” loop box would probably experience a revival anyway, as the new fiber optic cable should probably also be installed in the existing installation 🙂

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Hobby-Nerd ohne wirtschaftliche Abhängigkeiten zur Swisscom

@Werner There are currently no fiber optic plans planned, at least there is nothing in the checker

When fiber optic comes, I can use the entire U72 for my LAN connection and the nice thing is that exposing the loop socket during installation is no longer my problem 😂

But it could also be that they choose a different route for the fiber optic or something like that. I’ve also seen installations where they didn’t use the telephone pipes at all

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@NilsL I would have used a PLC of the latest generation and set it so that the transmission line was deep but still sufficient. Then you have a good connection near the router (or better a distant switch) and you don’t interfere with the g.Fast signal.

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Roger G.
Swisscom (Schweiz) AG, Product Manager Wireline Access

@“x”#223975PLC will be difficult because there are different electricity meters. My old 500 Mbits MyStrom divider that I still had lying around couldn’t establish a connection

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@NilsL wrote:

…Theoretically, just pull a LAN cable through the empty pipe where the U72 also goes through and you’re good. The problem is that it has a loop box in between, we also know where it is, but it was more or less bricked over it, exposing it would be a huge deal

What do you think about that?

I would be interested in a photo of this situation because of how huge it is.

If this theoretical evil weren’t there, it would work with a separate cable.

Don’t want to speak badly, but do you not want to get your hands dirty or is there really no way to get this can?

OK, if there’s a huge piece of furniture in front of it or whatever else is in the way, I can understand it.

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#user63

@“x”#63There was more or less a kitchen built in front of it (i.e. for employees at lunchtime), you would probably have to remove the refrigerator and the wooden furniture… not funny

We’re not 100% sure that the box is there, but according to the pictures from earlier, it’s exactly there and it also roughly agrees with the electrical plans

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@NilsL
If it was just the fridge, I would give it a try.
When the box was cut out in the back wall of the furniture… by the kitchen builder.

Just “popping out” the fridge would be worth it.
Then no more.

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#user63

@“x”#63I’ll take a look at the whole thing with the customer and get back to you

But the customer doesn’t really care about such tinkering as long as everything runs smoothly

But of course I know for sure that I’ll be the first to be called if things don’t work and that will definitely be at an inopportune time 😂

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The question is whether something is clamped in this loop box or is it really just looped.
At best, you could pull in something new and use the existing one as a “drag wire”.

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@cybi The thick U72 is just looped, I don’t see why something should be clamped there

However, various thinner U72 for the individual telephone or ISDN sockets go through the same pipe back to this socket (everything is out of order, except for a BBR socket that was installed years ago, which the router is attached to)

However, since I assume that the U72 makes a U-bend in the socket, this will be rather difficult in combination with the other cables that are also in the socket. I don’t want to risk that we won’t have any cable at all

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OK
So as an expert I would have to say, actually no 🤣
But now I’m at an age where I say, if it’s stable, leave it like that 😉
Decku druf and just do something useful 😆

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@“x”#1027868Don’t worry, the customer knows what I did and that it isn’t optimal etc., I’m always very transparent about it

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