On Mon, Nov 17, 2003 at 07:59:08PM -0500, lee wrote: | Sorry to get off topic but I need to re-wire my DSL connection at home here | and need to buy some phone wire and am curious if there is a good/better/best | type of wire I should purchase..will be a direct run to my modem going about | 100' or so from my box.. Typically phones use Cat 0 (or is Cat 1 the lowest?) cable. That cable has 0 twists in it. 10BaseT (10Mbs) ethernet requires at least Cat 3, which has 3-5 twists per yard (or something like that). 100BaseT (100Mbs) ethernet requires at least Cat 5, which has 3-5 twists per foot (or something like that). Gigabit ethernet requires at least Cat 6 or 7, which has 3-5 twists per inch. (all of these are "UTP" - Unshielded Twisted Pair - type cables) Why are twists so important and why do the faster technologies need more twists in the cable? As an electric signal varies along a pair of wires, a magnetic field around the wires is created and then collapses. This field will induce a current in another wire that passes through the field. That induced current is "noise", because it intereferes with the electric current (signal) that is intentially being sent over that wire. Twisting the wires reduces the size of the generated magnetic field, and also reduces the cable's ability to pick up a signal from a nearby magnetic field. For voice-grade telephone, no twists are needed most of the time. For better signalling and less noise, get more twists. Using Cat 0 or Cat 3 should be fine, but the Cat 3 will cost more money. You *may* have noise problems with Cat 0 which will hurt your ability to connect, maintain a connection, and will limit transfer rates. Basically "more is better" when it comes to twists, but also "more costs more". It's up to you to find the desired return-on-investment for cable quality. HTH, -D -- If your life is a hard drive, Christ can be your backup. www: http://dman13.dyndns.org/~dman/ jabber: dman@dman13.dyndns.org
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