Cat 5 Cable

[discodave]

I was wondering if anyone would be able to help me?

I understand that cat 5 cable uses only 4 of the 8 individual wires in a cable. Is this the case with all network cable (excluding coaxial etc) ie that they have free transmission lines?

I have also looked at different network cards all for use on Ethernet and noticed that some have all of the pins fitted and some only a couple. Is it the case that the ones with all pins fitted are done so just for ease of production (or something similar) and the extra pins arnt actually used?

I look forward to hearing from someone

 

[Accessdabbler]

I'm learning about this stuff too so if I say something wrong, beat me with a stick and kill my dog...

There are 2 types of 100Base ethernet. One type (100BaseTX, I believe) uses 4 of the 8 wires, the other type (100BaseSomething) uses all 8 wires. Gigabit networks use all 8 wires as well. The 100Base ethernet types are not compatible with each other (due, in part, to the fact that they don't use the same number of wires).

People began running the 8-wire Cat5 because they were told they'd probably need all 8 wires in the future (which, as it seems, is now true!).

As for the cards, I'm not sure. I'll let someone else more knowledgable than I (in other words, my 6-year-old son) answer that...

 

[svermill]

The above is pretty much dead on. Cat 5 is just a spec for the cable (near-end and far-end cross-talk, etc.). It's true that some technologies use differing numbers of wires, but that has nothing to do with Cat 5. That has to do with 802.3whatever. Further, Cat 5 isn't just for LANs. I use it for T-1s all the time, as an example.

 

[jimbopalmer]

100baseTX uses 2 pair of cat 5 or better wire (and is what you really find in the real world)
100baseT4 uses 4 pair of cat 3 or better wire (and comes very close to only existing on spec sheets)
1000baseT uses 4 pair of cat 5 or better wire

a number of power over ethernet schemes use another pair of wires to power remote devices (IP telephones, Wireless Access Points, etc) so even if it is 100baseTX there may be power on pins 7 & 8

All versions of token ring I am aware of use all 4 pairs I tried to remain child-like, all I acheived was childish.