Cat. 5 cables - Shielded, Solid, Stranded

websurfer

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Feb 5, 2001
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Can anyone explain the difference to me? And maybe also what would be ideal for what...shielded is more expensive, but is that only for people who use this with other lines? Any help would be appreciated :)
 

cfjohnsn

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Dec 7, 2001
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The differences can be major or not even noticable. The things that you have to take into consideration are: 1. Are you running the cable near any electrical wires? 2. How straight is the run? 3. How far is the run?

1. If you are running near any electrical wires, you should use the shielded because it is designed to block out the interference that is usually associated with having the wires near each other.

2. If you have a straight run/drop, using solid is more of the de facto for the backbone. Usually, standed it used for runs that are alot more difficult (read lots of bends/turns) or for patch cables because there is less attenuation (the distance it takes for you to start dropping packets more frequently).

3. One of the most important factors is distance. There are industry standards as far as the distance that each type is still able to offer it's maximum results. If you have short runs (say in your house) then these won't even factor in. If you are doing this in an office/business, then make sure that you know the length of the run. This is one of the easier sites to get that info:
http://techsolutions.hp.com/dir_gigabit_external/training/techbrief6.html


 

ScottMac

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Mar 19, 2001
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Solid conductor cable is meant for static installation (like "in-the-wall") Because the conductor is solid, it doesn't tolerate repeated flexion.

Stranded conductor is meant for jumper cables (like from the wall-plate to the computer). Because the conductor is stranded it does tolerate flexion and a little more stretching force than solid.

Solid conductor has better transmission characteristics (like less loss). The "100 Meter rule" for Category-rated UTP is based on 90 meters being solid conductor cable with 5 meters at each end being stranded (jumpers).

"Shielded UTP" translates to "Shielded Unshielded Twisted Pair" To make it less confusing, when shileding is added to UTP it's called "Screened" UTP.

There isn't much in the way of Category 5 Shileded cable (screened UTP or Shielded Twisted Pair). Belden and IBM came up with some, and a new type of connector, to replace the "Type 1,6 &9" cables and Token-Ring-style connector. It was rated at what is now Cat 6, but it never really caught on (dead now, I think).

Improperly terminated shielded twisted pair (or sUTP) can cause more problems that it was meant to solve (i.e., gorund loops, noise collection and radiation, etc).

So far, the cable manufacturers have been able to improve performance with new insulative compounds and twist formulas (not all pair in the same cable are at the same twist count per foot, every manufacturer's twist rates are different). There was a minor stutter in the progress a few years ago when CFCs were banned; manufacturers had to come up with a suitable replacement for wire jacketing because the "teflon" stuff they were using was part of the ban.

Not all UTP is category rated. "Regular Phone Wire" is totally unrated (usually not even making Cat 3 level certification).

All components (Cable, connectors, panels, punch-down blocks, data outlets) have to match for the cable to be "Cat X" rated. I.e., to have a "Cat 5" rated connection from one computer to another, the connectors, cable, outlets, panels, and punch-downs (or whatever subset) all have to be specifically rated at Category 5. If any of those components are at Cat 3, then the entire system rates-out at Cat 3.

Another complication to Category-Level certification is installation. If the cable gets kinked, severly twisted, stretched, or crushed...it may be out-of-spec. If the connectors are not terminated properly (more than 1/2 inch exposed and/or untwisted), it's probably out-of-spec. If there's a bend in the cable less than 2" in diameter, the cable is out-of-spec. If there are more than two intermediate connections, then the cable isout of spec. If the total length "in the wall" is longer than 90 meters (~270 feet), the cable is out of spec.

Coax is still a better data transmission cable, but the topologys that use coax tend so suck beyond budget and maintenance tolerances.

Fiber still beats both, and EXCEPT for a 3M product (Volition...something like that) that makes fiber about as cheap & easy as UTP, most fiber requires fairly expensive tool kits (US$1000-2500) and skills for termination, and the components (connectors @ US$5-12) are much more expensive.

Anixter has been putting together a "Levels" program for Fiber for the last year or so to rate performance of (I believe) multimode fiber. Anixter "Levels" program for copper was the basis for the "Category" rating system now in use....so someday you may see "Categoty 11" rated fiber.

I hope this was helpful......


Good Luck, happy holidays...

Scott
 

websurfer

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Feb 5, 2001
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<< I hope this was helpful...... >>




WOW...Very much so.....Thank you cfjohnson and scottmac.
 

DrSpock

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Jun 18, 2001
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Do you guys have any prices for the solid, shielded, and stranded? I'm looking to network my house and i'm trying to find the best deal. I will running one cable down the side of my house (attic to the basement, router to switch), so would i use a solid cable or shielded cable for this?
 

ScottMac

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Mar 19, 2001
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Solid in the walls, stranded for the jumpers (pc-pc, router-pc, anythin that's not in the walls.....buy 'em & save yourself some grief).

To cable your house, buy solid conductor, 5e, make sure the connectors are ALSO rated for 5e. Terminate both ends in either a panel or a wall jack;those should ALSO be rated for Cat 5e. EVERY cable & component (including connectors) must be rated the same, or the system takes on the rating of the lowest-rated component...including connectors.

If you buy the cheap-ass, non-rated connectors, the system will be doing good to make Cat 3 (you'll be good for ten megabit...maybe)

If you don't know what "568A" or "568B" color codes look like, do a search, it's been posted a zillion times. If you don't terminate your cable accordig to the color codes specified in 568A or B, the cable (probably) won't work for faster then ten megabits

Good Luck

Scott
 

Kell

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Mar 25, 2001
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Just one thing I'd add to all the above--a few words on plenum-rated cable.

Safety regulations require that any Cat5 cable running in or near an air-duct area should be plenum-rated. Plenum-rated cable doesn't have any better shielding; it just doesn't give off toxic fumes when it burns. It also generally costs twice as much as non-plenum cable.

If you're installing cable professionally, the simplest way to stay within safety regulations is to use plenum whenever you're going behind a wall.
 

ScottMac

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Plenum--rated cable DOES give off toxic fumes, it just has a higher flash and burning temprature.

Plenum-rated cable is only necessary/required in commercial establishments, and then only if in a plenum air-space (some cities have code requiring plenum-rated cable still has to be in conduit...Like Chicago).

Plenum-rated cable has no more UV protection that standard UTP (it rots in the sunlight just like the regular stuff).

Plenum cable is the worst thing to use for jumpers (in case you had some laying around) because the stiffness of the jacket doesn't offer any way for strain-relief at the connector. Plenum cable is all solid conductor.

There is absolutely no valid reason to use plenum cable at home (unless it goes in the walls, and you got it for free).

FWIW

Scott


 

Nutz

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Sep 3, 2000
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<< If you don't know what "568A" or "568B" color codes look like, do a search, it's been posted a zillion times. If you don't terminate your cable accordig to the color codes specified in 568A or B, the cable (probably) won't work for faster then ten megabits >>



Not to nitpick, but I don't entirely agree with that statement. I see what you mean, but the color codes are standards TIA/EIA put down. The order is important, especially from a troubleshooting and signaling standpoint, but the signal quality isn't really degraded so much that it would kill 100Mbit transmission. You can pretty much cable the ends any way you choose, so as long as the pairs (1, 2 & 3, 6) match up at the opposite end of the cable (Or are crossed in the case of a cross-over cable).
 

spidey07

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Aug 4, 2000
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Nutz,

Each of the pairs in category 5 rated cable is twisted at a different rate. If a cable or cabling plant is not wired according to 568 a or b standards, well then the cable is out of spec. If a cable is out of spec then you can and will get unusual results.

Will you not be able to run 100 megabit if your out of spec? sometimes yes, sometimes no.



<< You can pretty much cable the ends any way you choose, so as long as the pairs (1, 2 & 3, 6) match up at the opposite end of the cable (Or are crossed in the case of a cross-over cable). >>

Please follow the eia/tia standards. I can't tell you how many times I've fixed weird network problems (in the 100s) that was related to the attitude of "standards don't matter, I'll wire it my way"
 

ScottMac

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Mar 19, 2001
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The problem with just wiring up the pairs (not according to the spec) such that the paire are side-by-side (instead of splitting the orange or green pair @3&6) is that you end up with a "split pair"...meaning that you are transmitting on one pair, and receiving on one wire each of two other pair. At that point, you've mostly negated the noise cancelling properties (inbound and outbound) of the cable. Your ear-end/far-end crosstalk/power-sum numers go right the **** out the window.

If it works at all, chances are it'll be intermittent and/or slow.

You can disagree, that's fine. You can wire your place ANY WAY you want, fer sher.....just stay out of the commercial arena where you're gonna cost someone a sh*tload of cash chasing cable-related bugs.

Would you want someone to fix your car or an airplane you're riding in the way they see fit, because they don't believe doing it according to the standard?

It doesn't take any extra work to do it right, so why not?

(/end pet peeve mode)

FWIW

Scott
 

Nutz

Senior member
Sep 3, 2000
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<< The order is important, especially from a troubleshooting and signaling standpoint >>


Like I said, I agree with sticking to the standards. There's a reason we use them. But short lenghts and just futzing around you don't really need to be presise to get 100Mbit. I've made some jury-rigged configs in my time, usually with no problems.

Quick question though. What's up with Cisco's cables? Have you guys ever pinned out a console cable before. I have one thats Straigh through with all solid colors and then all striped, and another one we have has 1-7 and 2-8. Just weird pairs to choose for transmission I suppose.
 

ScottMac

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The Cisco console cables vary, depending on which line of Cisco stuff you're working on.

Some use straight-through, some use a "roll-over" cable (order exactly reversed 1->8, 8-->1), and some use crossover (only some pin-pairs swapped).

I think the powder blue cables are the rollover and the black are staraight-through...and according to some Cisco study materials I've seen, the "rollover" cable is the most widely used (most routers and switches).

FWIW

Scott
 

ScottMac

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Mar 19, 2001
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You are correct.

1&2, 7&8 = DDS, ATM copper
1&2, 4&5 = T1

1&2, 3&6 = Ethernet UTP (Cat3, Cat5)

1-8 (both ways, same four pair) = Gigabit Copper. (Cat5, 5e)
There is no such thing as a gig crossover cable.

(This space intentionally left (almost) blank) = Token Ring

All duplex fiber = 1&2 ;-)


Just keep plugging in cables till you find one that works...(then find out it was #*&*%&^$ HyperTerminal wasn't working).


Happy Holidays, Take care

Scott
 

spidey07

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Aug 4, 2000
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thanks scott (aka CableGOD).

token ring = 3,4,5,6 I believe. Haven't touched the stuff in 3 years. Nice of them to put it on the same pair as a live analog phone - mmmmmm ring voltage....mmmmmmm.
 

Nutz

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Sep 3, 2000
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<<
Just keep plugging in cables till you find one that works...(then find out it was #*&*%&^$ HyperTerminal wasn't working).
>>



Ain't that the damn truth!
 

ScottMac

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Mar 19, 2001
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You mean like...." Ooooops, I forgot to disable my PalmSync program?" Or redirected out the IR port, OR you forget that the terminal is set for your modem (so you could change a few parms), OR..you can't figure out why it's so hard to the get video plug for your monmitor to stay in...and realize you've just mutilated your seiral port, or or or or .....I swear, there's always some 'gator just waiting to bite you in the butt....ya gotta stay on your toes.

But, given that all the hardware is good, the cable is right, and I really AM plugged into an appropriate serial console port...HyperTerm for WIN9X is(IMHO) the biggest piece of suckware since the IBM "Asynchronous Terminal Program" that came out with the PC (but at least, if you could figure it out, it worked).

Secure CRT has been good to me, it does all the SSH stuff, Telnet, and serial terminal...I like it. Not cheap, but (to me) worth the price.

FWIW

Scott
(Glad to see Spidey jump back into the pool!)