atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Cat 3 vs. Cat 5e for Voice

Okay, guys, per justbill's request, here is the question and thread .....

Is Cat 5e better than Cat 3 for Voice and why ?

Go for it !!!

CAT5 because the tighter twists reduce crosstalk?

Grrrrrr :bang: :bang: :bang:

-Hal

For those who missed it, this discussion sprouted up from this thread: https://www.sundance-communications.com/forum/ultimatebb.php?/ubb/get_topic/f/24/t/000230.html

I don't think the question should be "Is Cat 5e better than Cat 3 for Voice and why ?" I don't think we'd see many "yes" votes, at least not with supportive arguments.

A better question might be "Does it make sense to run all Cat5e or better cable for voice as well as data?"

Here's my 1/2 cent........... For POTS lines it makes no difference. Howsomever{like that new word?}, if you ever want to use the remaining pairs in that cable CAT 3 may not do the job. If you run CAT 5 or CAT 6 you can always use the remaining pairs for data,video,alarm, or .....who knows. As Avaya used to say "reserved for future use".

In this day an age if I were pulling cable for future I'd put a voice cable and a network cable and probably RG6, there's no reason to use one cable for both unless there is absolutely no choice due to poor planning on someone's part in the first place.

I know you are just trying to make a point but I would highly recommend against using cat 5e for any alarm application (with the exception of providing dial tone to the panel which should be a dedicated home run anyway) especially if you are "stealing" a spare pair.

I think Bill nailed it. For a residence, I Pull at least one cat 5e preferable two to each location along with a two pair cat 3 run and at least 1 rg6 (again preferable two). This covers voice, data, and video with a spare cat 5 for "future use".

And last but not least if it is new construction or the place is gutted I try to run "smurf tube" as often as possible, that way if you ever need a change...no problem.

I would actually sat CAT 5 is WORSE for voice. The added twists add to your loop limit for a digital or analog phone. Understand CAT5E CAT6 etc was designed for 100 meter runs not 1000' runs.

On the other hand, CAT 6E & 6A cables use 23 gauge wire as opposed to 24 gauge used by CAT 3 & 5.

Be careful what you mix. If you try to run a POTS trunk through the same cable with many digital phone systems, the ring voltage will choke the data and drop the call.

Oh, and to sum up Hal's growl, a chain is only as strong as its weakest link.

I did a job where the customer bought all the cable. He went to an alarm supply place...they sold him quad for the phones because in their words 'there was no cat 3 anymore'. this was 3 years ago!

Lets debunk the crosstalk myth shall we. here is the cut and paste for what crosstalk really is.

Any two adjacent conductors can be considered as a capacitor, although the capacitance will be small unless the conductors are close together or long. This (unwanted) effect is termed "stray capacitance". Stray capacitance can allow signals to leak between circuits, and is a limiting factor for correct functioning of circuits at high frequency.

So lets dumb it down for my sake because I just don't get these things sometimes. What is a tightly wound pair of wires? is it not two conductors close together. I also believe that Cat5 is used to push high freq's right.

So loose wires can run at longer distance than tight wires right? and what freq's are most Telco signals at? I believe they are low right?

I just what someone to read this thread and put there own mind to work on the correct answers. That's not to say that everyone has a point and may be correct but lets give everyone a chance to exercise the huge muscle on our shoulders.

A ringing phone may also cause a false alarm on a alarm panel if it is run on the same cable or even parallel to a phone line

Waine, Don't know if I can get this but I'll try. Back in the days of open wire (yes I worked on it) we would have ac inductance and also inductance from one line to another. So what did they do to fix this? They rolled the wire on poles with only one circuit. On poles with cross arms and many circuits they put tramps in the lines. Result, this would bleed off the inductance (capacitance). So when cable came along they used the same theory and determined how many twist per foot kept this problem from happening. So the tighter the twist, the less problem inducing a signal from one pair to another they found the match and left it at that. Using a tighter twist for voice is not going to improve the voice as that problem was resolve long before networking was ever thought of, won't hurt it, but won't help either. With your network cables your seeing how fast at what length you can push a measured amount of information, the length is as critical as the number of twist per foot. You could never, over wire, push networking data as far as voice ( I said "networking" data on purpose). This may not make any sense, I'm just trying to explain how the twisting of the wire came about and why. CAT 5 for voice? Sure it will work, but not any better. I'm not even going to get into frequency, as you would have to also get into the roll off of different frequencys and the levels they are transmitted.

Bill, you got it. The wave form match of the wiring allowed the sine wave of the inductive frequency to be matched, thereby nullifying it.

Remember riding down the road and watching one wire going up and down and in and out? Just like the sine way on the screen on a oscillation scope.

Boy am I glad another "mature" person knew what the heck I was trying to say. :toast:

Well, here's my 99 cents worth, and probably 99 paragraphs:

Hal's not the only one growling. He and I both work in both the electrical and telecommunications businesses, so we can speak with either hat on our heads. We also understand the clear differences in these trades and aren't shy about discussing them. Personally, I have a huge problem with uneducated persons attempting to change decades-old standards. Why, if it worked for so long is it no longer capable of doing so? One word: HYPE.

If you have deep pockets, by all means run whatever type of cable you want. If a phone call to your grandmother sounds better since you ran Cat5 cable for your telephones in your house, hey, that is great. In most cases, you can run speaker wire, thermostat wire or even 14/2 Romex for a local telephone jack and it will work just fine.

You can even get away with this on key or PBX station cable runs. The systems are very tolerant of wiring inconsistencies. Much of this discussion revolves around cable manufacturers banding together to scare people (typically architects, electricians, junior telecom managers or IT people). They convince these people to believe that more expensive is better. I wonder why? Since these people are the "authority figures" on the project, we see installations that consist of wiring that is much more difficult to work with for such simple applications like voice or DSL.

I suppose that we are just considered to be the ignorant telephone installers. We are supposed to just do whatever these people were told at a seminar. Maybe even what they read in a computer/electrical contracting magazine said we should. Uh, OK, maybe we should stop trying to save our customers from needless expense.

Telephone line quality cannot be improved at the end of the run with "better" cable. Signal quality that was lost miles away can't be regenerated by using "better" cable at the far end.

Here I go again with simplistic comparisons. Let's say you have a pipe line that can only deliver one gallon per hour but you need five. Will increasing the pipeline size where it enters the building give you five times the delivery? Of course not!

I pray that nobody here actually thinks that this could happen. Still, the Cat3, Cat5,6,7,8,9..... argument continues. Everyone who gets their "wings" for attending cabling certification classes have succeeded in being brainwashed into overselling. I will sell the customer anything that they are told that they need, but I don't feel guilty about it since they don't want to hear what I have to say.

This reminds me of the "Monster Cable" marketing or "gold" connectors. Put a scary or fancy buzzword name on a product and people will scare themselves into buying it at at ten times what it's worth and twenty times what they need.

People: You need to listen! A poor-quality circuit of ANY kind delivered to the premises from the telco via copper CANNOT, REPEAT CANNOT be improved or restored by using more-expensive cable. Nobody here is going to disprove this.

PS: Just for the record, I have four VOIP telephones at my house working from my system at my office. All four are connected using spare pairs in Western Electric "D" inside wiring cable runs (no category rating at the time of manufacture). I have Panasonic phones running on the other two pairs at these stations.

I swore to myself that I wouldn't pull out my soap box for the rest of the year, but I can't help it. I am addicted to correcting ignorance, though I feel as if I am fighting a losing battle. I let myself down in doing this, but I hope that I helped someone or saved them some money in the process.

I wondered when we were going to get a long overdue ED-itorial. :thumb:

:bow:

hey i was told once phone lines COULD be run on barbed wire! wouldn't want to be the tech on that.
But seriously, I was volunteering at a shelter home today doing painting. A customer of mine is on the board there and wants me to fix up a phone line he ran. He used 18/4C alarm wire...it works fine but the cable itself was run poorly in one of those 'emergency' installs...so being the good guy I am, I told him I would give my time to clean it up.

Nice guy, Jeff. Keep up the good work.

And, yes, in the old days private held exchanges did as they wished, including using a barbed wire fence as the return on circuits, or in lieu of a grounded talk circuit.

If you are ever lost in Kansas, behind the Eisenhower Museum is the Ford County Museum and the Independent Telephony Museum. They also have the Greyhound Hall of Fame. All just off I-70 about 3 hours west of Kansas City at Abilene.

(How's that for advertising ?)

I once used an entire metal building for one "side" of a station out of a Comdial system.

The customer did not want new cables installed so I was forced to work with what was there from many years before. (I worked for another company back then so the only choice I had was to quit or do the job the way the boss said to) Anyway, it was getting late on a Friday night and I had been at the job site since 5 AM. and this was the last station to be installed. We had maxed out the cable pairs by adding a few stations where there were none before.

The run was around 400 feet and there was no way in hell I was gonna stay and run it that night but I knew the phone had to be working by the next morning so I used the metal building for the white/blue side of the circuit.

I could hear a little bit of static but the customer didn't seem to notice it. I was going to go back and run a new cable but I never got a round to it before I quit that job.

I know this was not the right way of doing things, the point I'm trying to make is that voice signal is very forgiving like so many of you have said.

I'll bet I'm not the only one that has used this method.

I just like the sound of running two phone lines on quad.

Make the length (of the quad cable) long enough and you get a free conference feature!

POTS lines are balanced 600 ohm line, and using a tighter twist will indeed have better rejection to common mode interference and cross talk from other adjacent pairs. It will not however improve the audio quality aside from reducing potential hum, RF interference and adjacent pair crosstalk. Is it worth the extra cost? depends on who is doing the cabling. It's easier to tell an electrician to put four runs of cat 5 to each box than mixing cat 3 and 5 and finding out later he screwed it up. Look up Common mode rejection ratio (CMRR) pertaining to audio lines on the net and you'll find a plethora of info; after all, a telephone line is just a long balanced audio line.
[URL=https://en.wikipedia.org/wiki/Common-mode_rejection_ratio][/URL]

Regarding audio quality of a phone line, the telephone is the most limiting factor. In fact when I have done remote broadcast feeds via phone line, the audio quality can actually be pretty good if you drive it with a good quality transformer at +4db.

No harm in running cat5 aside from difference in cost. It sure beats the old Z-wire with parallel conductors.

I am an electronics technician, and deal with these kind of issues all the time in broadcast studios and recording studios, where noise must be kept to a minimum on all lines. Same theory applies to a phone lines.

POTS lines are balanced 600 ohm line, and using a tighter twist will indeed have better rejection to common mode interference and cross talk from other adjacent pairs.

True but you have to consider the levels in the balanced line. If you are talking about a low level mic line then, yes cable construction is an important consideration because even small amounts of interference will get into the audio.

With a POTS line the level is much higher and the subscriber equipment is basically passive so the line can tolerate a much higher level of interference before it becomes objectionable. The most usual cause of hum and noise on a POTS line is from an unbalanced condition.

The additional twists present in a CAT 5 and higher wire will make no difference to POTS performance. That it would be beneficial goes against nearly a century of telephone engineering. It's always been easy enough to make a wire with the same twist characteristics as CAT5. If there was some advantage don't you think it would have been put into use many years ago?

It's easier to tell an electrician to put four runs of cat 5 to each box than mixing cat 3 and 5

:rofl: The chances of some sparkies getting it right would have nothing to do with me telling them how to do it, even if I were standing there. Besides, they are not the ones doing the termination.

-Hal

I partially agree with you, but the phone company has always juggled "good enough" and costs. Thats why we have a voice bandwidth of less than 4khz, it's good enough. Phone lines run in a tray with other data lines, speaker lines, Low voltage control cables etc. can certainly benefit from every bit of noise rejection possible. 40 years ago and earlier, these weren't so much of a concern because there wasn't all the added noise generating sources in the average building. It doesn't seem too many years back that the telco decided Z wire with parallel conductors maybe wasn't the best thing to wire a building with for exactly the reasons cited above, but thousands of miles of the stuff was still installed until someone woke up and decided twisted pair offered better noise rejection.

Thats why we have a voice bandwidth of less than 4khz, it's good enough.

Yeah and what do we have now with cell phones and VoIP? Voice quality doesn't even come close to that and people have been brainwashed into liking it!

It doesn't seem too many years back that the telco decided Z wire with parallel conductors maybe wasn't the best thing to wire a building with...

Quad or JK wire was fine in the days of one line installations. But the proliferation of two and more lines even in residential required twisted pairs, not for noise rejection but for crosstalk rejection. This is nothing new.

-Hal

My understanding about Quad or JK wire is that it was designed to look nice (it's perfectly round) in baseboard exposed applications at the expense of crosstalk rejection.

For prewired installations, where the wire is is not exposed, twisted pair is supposed to be used. I know of houses built in the mid-60s that were prewired by Bell with 6-pair cable. Even back then they knew that people might want an additional line.

Of course all of this went out the window after deregulation and Bell stopped doing the prewiring. Then most everyone used Quad or JK for prewires until the mid 90s.

As for here, this area was an independent (Contel) and they always used quad for prewires as far as I've seen.

Bell with 6 pair was cat 3.... better than JK and it was used around 1967 and then on. General cable or texarcana made this stuff for years.

My understanding about Quad or JK wire is that it was designed to look nice (it's perfectly round) in baseboard exposed applications...

I'm actually holding a sample of 2 pair cat3 inside wire in my teeth as I type this. Made by General Cable and it's perfectly round.

Wish I could get more of it. Seems it was made for the BOC's.

-Hal

Hal, you are speaking of "L" station wire, a twisted pair version of quad. I got my hands on some small 125 foot coils of it in nice little plastic cases. I think they were meant for installers to carry in their bag for short surface runs. Regardless, they are pretty cool items.

Brian, I know that you speak of Prince William County's former Contel, then GTE and now "Verizon" strong hold. You are right, they used that awful "band aid beige" quad and stapled it to the studs in new prewires. Permanently malfunctioning from the day it was installed.

Charlie, I remember the unjacketed 6 pair and then later jacketed 6 pair that Bell companies used for prewire loops (key word is LOOPS). A proper prewire brought both ends of the loop back to the protector so that if it was cut at any point, it would still work since it was being fed from both ends. It would take a second prewire cut to create a service-affecting issue. Bell did their homework on reliability even when the fault was due to the actions of others.

Their method was two-fold. They also upsold customers on two-lines (1A2) in the late 1960's. Six pairs was just enough to provide two lines on 1A2 phones throughout the home. They even came up with 12-pin plugs and jacks and even six-pair line cords for the 1A2 sets. For those of you who might not have seen these, the pins were in a round pattern with a keyed center post to force the proper positioning of the plug (very similar to the base of a vacuum tube or octal-base relay).

A crafty installer could even split the appropriate pairs and derrive a seventh circuit for a common ringer. I did a bunch of those installs in New Jersey, where every house built in the 1960's was wired with this stuff. They kept using it here in Virginia until around 1975. They then switched over to "H" station wire, which was 3-pair twisted pair (no category) and had a weatherized (sunlight resistant) jacket. This was because protectors were being installed oudoors exclusively in new residential construction.

I kept prewiring with the unjacketed 6 pair, using drive rings, "B" plastic tubes, etc. until the sparkies drove that business away from us. I still had about ten 1,500 foot reels of the Texarkanna unjacketed cable until about two years ago when I had to retire it to the recycling bin.

Once again, Ed, that was quite interesting.

Yes, that is in Prince William County--Contel always struck me as a 2nd-rate telephone company. And what a name.."Con"tel.

On the subject of inside wire, I used to think that cable color coded red/green/black/yellow is never twisted pair but I have found a couple of exceptions:

Radio Shack's telephone cable was (is?) actually twisted pair and has been for a long time. As of the last time I checked (a couple years ago) it does not claim Cat 3 compliance but it appears to still be twisted pair.

Home Depot sells "Cat 3" telephone cable under the RCA name with red/green/black/yellow color coding. As I recall this comes close to being perfectly round but it will deform quite easily unlike traditional quad wire which is solidly packed with jacket material, extruded around the conductors.

Home Depot does not sell any sort of "quad" wire. Lowe's, however, still does--and under the Bellsouth or Southwestern Bell name, no less.

I think that 6-conductor cable with red/green/black/yellow/white/blue conductors is usually twisted pair but I have only rarely seen this type of cable.

Hal, you are speaking of "L" station wire, a twisted pair version of quad.

Dunno. This stuff uses the w/bl-w/or colors, 22ga, has a rip cord and a rather heavy (light beige)jacket. Listed CMX outdoor CAT3. General Cable #110417E3 BOC. Really nice stuff.

I also know they had a similar black (outdoor) 6 pair version that was made by Belden/CDT for runs to outdoor NIs and terminals. This was provided as a loose coil that was to be used with a non-disposable dispensing reel. I should have a piece of that around someplace too.

-Hal

You are correct, Hal. That's not what I was speaking of when I mentioned "L" station wire. It appeared to be identical to "D" station wire but the red/green and black/yellow were twisted into pairs. The jacket was ivory colored (I believe that it was also made in light olive gray) and it was thick enough to be perfectly round and keep it's shape. It definitely didn't have a rip cord, so there's no doubt that what you have is not what I was thinking.

So Ed...
L is twisted pairs and D is untwisted pairs, aka quad aka JK?

D station wire is also known as quad or JK.

D inside wiring cable is twisted pair and is available in 24 and 22 gauge. It's similar to standard UTP cable except that it has a heavier rip cord and is designed for indoor/outdoor use.

I've seen cable printed with "AT&T-D" on it, I expect that is D inside wiring cable?

I believe that the "AT&T-D" was just a plant identifier. They had a manufacturing facility in Denver. I have also seen "AT&T-O" that I assume indicated their Omaha works, "AT&T-P" for the Phoenix plant, but I can't say for sure. The cable type would be marked either DSW or DIW. These cables were primarily produced for use by Bell companies.

Their commercial products were only given a numerical identifier, for example 1021 was category 3, 1041 was category 4 and 1061 was category 5.

Ed, so which one is L wire?

J station wire was actually still quad, but the conductors were spiraled instead of being laid parallel inside the jacket. L station wire was twisted pair (red/green and black/yellow).

I typically run Cat5e solid blue for data, Cat5e solid white for voice and RG6 quad to each wallplate.


I like the higher cats do the less crosstalk

:scratch:

</font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Originally posted by justbill:
<strong> :rofl:

These cable designations are interesting, speaking as someone from a country where we've used completely different systems for identification.

So, if I have collected the above together correctly:

D is the regular old-style quad station wire with (near-enough) parallel conductors.

J puts the wires in a light spiral (all four spiraled together, or spiraled in two pairs?)

L is individual twisted pairs (red/green, black/yellow).

H is the 3-pair version of L (red/green, black/yellow, white/blue).

Was there ever any reason for these specific designations?

And why JK which appears to be the same as D? I've seen regular quad referred to as JK before, but never knew why.

Any more single/double-letter designations?

Paul, you are close. H station wire was 3 pair, but it used white/blue, white/orange and white/green pairs instead of tradional "quad" wire colors. It was also only available in 24 AWG.

D station wire was available in 22 or 24 AWG. I am pretty sure that J and L were only available in 22 AWG.

Yes, "JK" is the same thing as "D" station wire. I really don't know how this terminology came about. I do know that there was another type of quad wire from the late 1950's to the mid 1960's that was referred to as "JKT" that used a larger (20 AWG) conductor. Because of it's larger size, it really cannot be used with IDC connectors.

The only other lettered wire types that I can think of refer to cross connect wire. We have "F type that is 24 AWG and the twists are comparable to CAT3 rating, and it comes in a variety of colors and pair counts. "G" type is 22 AWG and is used in outdoor cross connect cabinets, but it's only made in white/violet single pair construction.

We also have "E" bridle wire, which is one pair or quad, but it's black vinyl insulated for each conductor. It is used to connect between outdoor terminals or terminals on poles. It was originally used to make the transition between open wire circuits and local drop wires.

Home2Point0, you're new here ain't ya.

-Hal

hbiss..I was being sarcastic and trying to make a joke that I know old school wiring guys would get.

Thanks for letting us know you weren't serious, thought we had another one of those @%!!! on our hands.

Whew! You had me scared there for a moment.

-Hal

I started on Nortel Meridians back 10 years ago and was taught by a 25 year bellsouth vet the ropes. I'm young but I grew up around old school technologies that gave me the foundation for what I know today. Me I idolize old Bell Guys. Those were my heros..Call me a geek but they were.

The story on JKT (or so the story goes) meant "jacketed" vs. the cloth covered three lead "house" wire that had "thumb tacks" nailed through it to hold it to the base board. It was a three lead 19 ga. covered (jacketed) IW (inside wiring) that was stapled. The JKT is what I started with back in the day with Bell.

The different ga. bridle wire had two types. The larger had a ridge (ring) on one conductor and the smaller had a color (red) annealed under the rubber coating. The larger was used on open wire, the smaller on "drops" out of terminals.

Anyway, that was the local usage and material 40-some odd years ago at SWBT.

Interesting. So I wonder whether JK was just a shortening of JKT?

We've had quite a variety of color coding used here over the years. We never used the American red/green/black/yellow standard, but back in the GPO days the standard "quad" wire used for internal wiring was blue/orange/green/brown (blue & orange for tip & ring).

Flexible cords on the phones, however, were white/red/green/blue (white & red as tip & ring respectively, and generally bell return on the green which would be strapped to white on single-party line or to local ground for party-line service).

Internal cabling changed over to the standard white/blue, white/orange, white/green etc. pairs in the early 1980s.

Just to add to the confusion, drop wires installed for new services now use a completely different scheme again -- orange/white/green/black.

Both will support voice just fine. An argument could be made that C5e would be more immune to possible external interference (running too close to power, fluorescent lighting, etc), but generally both will suffice.

With C5e not costing much more than C3 for non-plenum applications I think a good business sense can be made for using C5e. In plenum applications there will be a bigger savings with using C3.

Of course, C5e does give you the added flexibility of using it for >10Mb for data transmission.

I, personally, would spec C5e. The cost difference is minimal and it is a more flexible install. But, that's just me.

I have never seen this. I just picked up two 400ft boxes of Aerial 6pr (Superior Essex) and they contain the standard color coding.

I know AT&T (in the midwest) uses the same aerial service wire I just purchased.

Who is using this new color code and do you know why?

Chad:

Paul is in the UK (as in England). That's why it's so different. It's being used by BT (British Telecom), the UK equivalent of Bell here in the US.

I do share in your question though. It seems that most of the world has accepted the standard US color code for network wiring being white/blue through white/brown. In the US, telephone has followed suit, even though telephone came first and actually invented this color code! It doesn't make sense that separate color codes are used for different cable types "across the pond".

I am sure that Paul will shed some light on this topic.

Take a look at where Paul is from - Norfolk, England. That would account for the different color coding.

Sorry for any confusion!

As to why BT adopted this new scheme with orange/white for the first/main pair on just the drops, I have no idea. It does seem odd, as it's a fairly new standard and W/B, W/O, W/G etc. were already firmly established.

The white/red for tip/ring on internal flexible cords here goes back many, many years. If I recall correctly, these were also the colors used on switchboard cords, with the addition of blue for sleeve.

There might be something about the origins of our old color coding schemes in Atkinson's "Telephony," a large two-volume set which was the "bible" of telephone systems 50 years ago. I'll see if I can find anything.

Maybe the Brits will do ANYTHING to avoid the appearance of being American. You all know how backwards we are.