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

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.