OT: Direct Bury LAN cable

You may have done it, and it may have worked /for you/ - but you haven't really analyzed the results, just got a shared telephone line and computer connection that APPEARS to work properly. Could just be dumb luck, because the experts say don't do it.

Network wire is cheap compared to the labor of installing it.

I have talked with people with real computer network training and all the fancy testing gear - double up the lines like that (either two network connections or network and a couple of phone lines), and you get a lot of errors on the computer lines.

On a home network at 10MB speeds the time lost to your computers at each end of the link error checking, failing, and resending a few (or a lot of) data packets is not noticed, but on a heavily used business network running 100MB shared among dozens of computers it impacts the actual data throughput you can get. And it can be bursty errors from crosstalk - when the phone is idle the network runs fine, use the phone and the network goes to heck.

I don't have the fancy TDR's and network analyzers either, so I do it the right way (one connection per cable), use a simple network wiring checker to look for shorts crosses and opens, and don't sweat whether it will stop working.

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That's why the rules call for 36" or deeper under roads, so the pipes don't crush. Better yet, get the trench dug and the pipes (plural) laid, and call the local ready-mix for a few truckloads of "One Sack Slurry" - man-made sandstone, concrete light on cement. Backfill six inches or a foot above the conduits, and then fill the rest with dirt - if the area is paved and you're using a trencher, just fill the whole slot with slurry up to the bottom of the pavement.

It should spread the loads and provide some crush protection for the pipes, provide some stability to avoid frost heave damage to the pipes, and it won't settle so the pavement patch won't either. And it can be dug up fairly easily if you ever need to get back in there.

Me, I'm staying in SoCal, where permafrost is never an issue. ;-)

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Using Leviton RJ-45's, use the top or "B" color code and connect the orange and grean pair to the RJ-45, use the blue and brown for telephone.

Let us know how it works.

Cat 5 or Cat 6, properly deployed, will NOT have crosstalk problems using the phone and data together. It is part of the Cat5 spec.

The electrical code (for my area at least) only addresses power wiring, and you are not obligated to follow it for network wiring. However, it seems like good advice since CAT5 is more fragile than, say 12/3. It says 900mm (35.4") cable depth under a vehicular traffic area or 750 mm (29.5") if a minimum 38mm (1.5") plank is laid 3" above the cable as protection. In all cases there is 3" (75mm) of sand above and below the cable.

I strongly agree with: conduit as opposed to direct bury, larger conduit than you think you need, more cables than you think you need, don't try to save pennies by using 'spare' pairs for phone lines, good separation between power and data, and throw a 1" pex in the trench while its open. Oh, yeah, and 'call before you dig'.

It's sooo much easier to do a bit more than you may have to the first time than to fix it later.... If the original phone line had been laid in an oversized conduit, you wouldn't be going through this exercise now, right?

mickey

Thank you.

Jim Stewart wrote in news:bp3bgq$ snipped-for-privacy@library1.airnews.net:

Since you are going to the trouble of digging a trench and laying pipe for your 250' I'd like to suggest that the cost of a few extra lengths of cat5 is insignificant and good insurance, as suggested by other posters. Even at home depot prices its $20 a run or from better suppliers 1000' at $40 or so. Is it worth mucking about?

I think you will find you *will* have potential for problems with crosstalk with analog voice and data. They might not be obvious unless you get static on voice or you use some equipment to measure the data circuit. If you do you'll see lost packets and cross talk.Note that even

*properly* installed cat5 with one data circuit and molded ends gets crosstalk, just that the arrangement brings it down to an insignificant level at the rated speed. I think you'll find trying voice and data on the same cable over that length will appear as slow or give interrupted data connection at best and total failure at worst. For the same reason don't run the cat5 close to a power cable for any distance either.

I've been forced to run voice, digital and analog with data over 100' with cat5e riser shielded spec (normally only for use in patch) in commercial situation and it doesn't work well at all.

The Cat5 Spec is an elusive beast, theres about 10 different versions; Cat5, Cat5 10/100, Cat5e, Cat5 riser, Cat5 sheilded etc and everyone has thier own take or version of each one. The IEEE versions do not explicitly state that analog voice and data should or can run on the same cable of any spec. It does however state that with correct deployment running four pair analog voice is supported as per Cat4 or for instance two data circuits (2x2pair) but at 10mbs max only. It also states for instance that manually crimped rj45 connectors on single data circuits are only spec'ed for 10mbs max too, because of the problems of cross talk. Thats how sensitive this stuff is even at 10 mbs and it gets worse at 100 or Gbit.

For the rather small additional cost, ease of use, ease of plugging and termination and assurance that it will work rather than theories that it should, I'd run several cat5's and seperate voice and data.

If you have trouble getting the black well pipe to unroll straight consider plugging the ends and throwing it into a tub of warm, but not hand burinig hot water for a few minutes.

Another thought. Thre is a machine that can punch a hole large enough for a

2" conduit under a dirveway by displacing the dirt. Depending on soil conditions it can go over 20' laterally. No damage to the dirveway and nothing to refill. A guy up the road has one, but I don't know the proper name for the machine 8o(.

Not sure what your weather is like in your area but I would not recommend it due to storms (lightening). We have major problems here in FL with underground data cable and have, for all practical purposes, eliminated doing it due to inductive issues and blowing out the switches and NIC cards. If we have to run cable then it is fiber to connect the various buildings.

Still think wireless is your best, fastest approach to the problem.

Merle

Is there a source of SC (square) multimode fiber to RJ11 interfaces for less than hundreds of dollars? I picked up a 50 meter length of multimode fiber at a hamfest, but haven't yet found affordable converters 8o(.

FWIW, the National Electrical Code (NEC) defines an underground raceway (conduit) as a "wet location". When placing power wires in such a raceway it must have a water proof rating, like TW or THHW.

A PVC or Teflon jacket CAT5 should be ok. But, if there are any tears in the jacket or splices in the run one might have water in the pair bundles. Which will affect performance of the wire plant.

:>>

:>>>In article , :>>>Karl Townsend wrote: :>>>

:>>>

:>>>>I'm having to dig my parking lot up between the sales barn and the house :>>>>this weekend to replace the telephone line. BIG JOB. Hope I miss the :> :> all :> :>>>>the gas lines, power lines, and security cables Got to be done :> :> right :> :>>>>away as the ground is starting to stay frozen. :>>>>

:>>>>While the trench is open I'd like to throw in a direct bury Lan computer :>>>>cable. And forget about a wireless network. What should I use? The run :> :> will :> :>>>>be 250 feet FWIW. :>>>>

:>>>>Karl Townsend :>>>>

:>>>>

:>>>

:>>>

:>>>How about a piece of 1 inch or better conduit or PVC pipe. Then you can :> :> pull :> :>>>what ever you want through and replace it as needed (cables don't last :>>>forever. Not even fiber) :>>

:>>Agreed. Schedule 80 pvc pipe + cheap CAT5 will undoubtedly be :>>cheaper than direct burial CAT5. :>>

:>>BTW, 10BaseT ethernet only uses 2 pairs. You could use the :>>other 2 for phone lines and only lay 1 cable. :>>

:> :> :> Not really. The crosstalk at that distance might kill the network. :> :> Seperate CAT5 or CAT6 for the network and CAT3 for the voice.

: Bullshit. I've done it many times and it's never been a problem.

You don't see a problem with 100+ volt ac ringing voltage on a pair next to your data circuits?

How do you define "it's never been a problem"?

Why take a chance when cat3 wire is dirt cheap for the phone cks? Just pull it with the data ckts.

Tom

Merle speaks volumes here. my experience is with longer runs between computers at Sac Peak Observatory, a very early custom designed, "data link". until the _customer_ modified the product with opto-isolators, it was basically useless. --Loren

...>

it is likely hydralic, there may be plans on the web(?). this type of device has been around for decades. not very good for rocky strata, but in an area that is already improved this s/b no issue. --Loren

Not a bit. Properly designed ethernet will withstand

1000 volt common-mode transient. Ethernet protocols assume an unreliable connection and will recover from transient errors.

As in I've strung or used a couple thousand feet that way without a problem. And that I understand from a design standpoint that it's not a problem.

Read my last post on the subject.

Do what you want. I don't care. My arguement here is that it's safe and reliable to mix ethernet and telco voice. If you don't believe me, run what you want, it's a free country.

I've noticed that in CAT 5a the orange and green pairs have a different number of twists per inch, presumably because otherwise each wire would always come around to touch the same wire of the other pair. That would negate the effect of twisting the wire. The brown and blue pairs are also different from each other but have the same twist spacing as the orange and green.

If you are using your one sack slurry idea, I would strongly recommend placing a smooth surface material, such as masonite or even cheap drywall, along each side of the trench to avoid frost adhesion and subsequent heaving. Gerry :-)} London, Canada