who can settle this argument

Oct 13, 2012 11 Replies

A friend is doing his own network wiring. He told me what he did and I have serious doubts as to whether it will work at all. This is what he's done: he ran an underground shielded cable between metal junction boxes mounted on the outside of two buildings. The shield is grounded at one end, not connected to anything just wrapped and taped at the other, (this was my suggestion). So far everything sounds OK. now here's the interesting part. He's apparently taken a twenty foot network cable with RJ45's on either end, chopped it in half, and wire nutted this to the underground color for color at each end. He plans to connect this between the new computer which he hasn't received yet and the network. I told him that he should have used a termination block and offered that worst case this arrangement won't work at all. Best case he'll suffer a significant loss of speed. He doesn't believe that there will be any problem with this at all though, and if it is it would be minor. So who's right? Can this type of cob job work, and if so would performance be significantly compromised, and how much? Thanks, Lenny


if it was that simple, people wouldn't bother with the proper connectors. It may work, at low data rates. It may have problems with stray RF, or other problems with reliability.

Find a new friend that doesn't do their own network wiring. I'll resist the temptation to crosspost this to comp.dcom.wiring.

How far and what type of cable? If it's shielded CAT5E or CAT6 (ScTP, FTP, STP, S/UTP, etc) then there's a chance it will work. If the cable is some kind of microphone or signal cable, forget it.

Ummm.... He's suppose to use shielded RJ45 connectors.

Nope. No numbers for cable, length, or connectors.

Barf. That might work for slow 10BaseT/HDX (half duplex), but will not fly for FDX (full duplex), 100Mbits/sec or Gigabit.

What's on the other end of the cable?

If (and only if) the original cable is CAT5 or CAT6, then the easiest fix is to put RJ45 plugs or jacks at the end points. If he needs to add 10ft of CAT5 or CAT6 on each end, then do it with a proper patch cable. Lose the shielded (un-necessary) and the wire nuts.

Type 66 punch down blocks sorta work at 10mbits/sec, but screw up badly at 100mbits/sec (my experience). Type 110 punch down blocks do better, especially when they are specifically designed for networking. However, nothing is better than an RJ45 connector.

I don't care to speculate on exactly where it will screw up. I just know it will fails somewhere.

Incidentally, if this is a ham operator, and the shielding is to eliminate RFI, shielding is not going to help much. I know several super stations that are using 2.4 and 5.7GHz Wi-Fi in place of ethernet cable solely to eliminated RFI.

Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

This is probably OK, if by "network" he's shooting for connecting two 9600 baud lease line modems together.

Chuckle. I think I know where the friend got the wire nut idea: Suddenly, I have this craving for spaghetti.

Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

Assuming this is an Ethernet * connection...

Ethernet cables (even Cat6) aren't that expensive. Why does he need to make up his own cable?

This seems to be another example of a complex "solution" to a non-existant problem.

Yep, except it's not a solution because it probably will not work. Sigh, they're everywhere:

Another reason why it might not work:

More problems disguised as solutions:

Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

You've exposed the secret of why you never coil up excess network cable. Shame on you! ;-)

Every US tech needs at least one of these:

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Hmmm.... It won't fit:

-- Jeff Liebermann snipped-for-privacy@cruzio.com

150 Felker St #D
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Santa Cruz CA 95060
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Skype: JeffLiebermann AE6KS 831-336-2558

You know those are only installed in lawyer's homes.

I'm sort of numb to photos like that these days.

I really wish I was allowed to share photos of the bad stuff I've come across.

There was actually a device called "the moving cable" at a 1990s ISP I worked at that had a normal power plug connected to a male IEC connector. It had the obligatory electrical tape "lump" of a splice as you'd expect to see in something like that.

The end was shrouded so no pins were completely exposed, but the idea was you could move computers between racks, live by supplying power into the monitor power out socket that old power supplies had while unplugging the normal power connector.

I never got to witness it's use, but am still surprised everybody that did always fed power it power from the correct phase.

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