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Telephone Versus Computer Cabling


Telephone Versus Computer Cabling 101
Why you DO NOT need to install CAT 5 cable for everything!

In this tutorial I'll help you to understand why you don't need to pay for the more expensive wiring inside your building. It has come to my attention over the last couple of years that more and more often companies are requesting that "CAT5" or "Level5" wiring/cabling be installed for both phone systems and computer networks.



  • Phone systems and computer networks are very different in terms of how they work and how they're designed. (Stick with me; I PROMISE not to bore you!) Phone systems are generally designed to run just fine on the lowest grade of cable, which is "level1" or "CAT1", and are designed to run at distances up to 750-1000 feet. The manufacturers of phone systems have known and dealt with cabling problems for centuries, and therefore have had the time to work hard at making their systems, for the most part "bulletproof" when it comes to cabling issues and problems. If you were to look in the beginning of any new phone system "Installation Manual", all that they (the manufacturer) require is that the cable be "twisted pair" cable. The "level" is irrelevant. That's because the manufacturer's KNOW that people are going to re-use old cable that was in their building when they moved in.

    Computer networks are almost the direct opposite. Because networks as a whole are fairly new; the effect that network manufacturers are most interested in is speed. Because networks generally carry a large volume of data (at high speed) it is imperative that the cable cannot pick up any outside noise or interference. As well, most networks have a limitation on the length of cable that is much shorter than phones. The very longest cable in a network can't exceed 330 feet or so and still meet the ATT/Bellabs 568 standards. (Computer@330 feet versus phone system@750-1000 feet.)

    Think about it, even if you do run a cable out in the warehouse that is CAT5, you still can't run your computer on it because it is too long of a cable! The bottom line on this one is simple, folks. Run CAT5 for your computer network and CAT3 or lower for your phones. A typical phone cable, installed will cost you between $70.00 and $115.00 next to the same cable being run in CAT5 cable that will start around $135.00 and go up from there. You're looking at around a 35% to 40% difference in price, and no ascertainable difference in performance on your phone system.