Cat5 cabling - 2 pairs or 4 pairs?

[TomLyall]

Also Cat 5 networking only uses 2 pairs and not all 4.

er, now my turn to be pedantic.... 100 base ethernet will use all 4 pairs, 10 base uses 2

 

(brings back horrible memories of replacing in excess of 200 rj45's cus someone was told only to crimp two pairs...)

 

Tom

[peternewman]

tomlyall,

 

Also Cat 5 networking only uses 2 pairs and not all 4.

er, now my turn to be pedantic.... 100 base ethernet will use all 4 pairs, 10 base uses 2

 

I am not trying to start a slanging match or anything but this is not the case according to our very own Tom Baldwin RJ-45 Pinout

 

this was also backed up by various other sites on the web.

 

PN

[TomLyall]

tomlyall,

 

Also Cat 5 networking only uses 2 pairs and not all 4.

er, now my turn to be pedantic.... 100 base ethernet will use all 4 pairs, 10 base uses 2

 

I am not trying to start a slanging match or anything but this is not the case according to our very own Tom Baldwin RJ-45 Pinout

 

this was also backed up by various other sites on the web.

 

PN

again, not trying to argue but if you look on toms website again, you'll see it clearly states that the said configuration is for '10BaseT networking'

[peternewman]

Oops

 

I feel really stupid now. Must look more carefully when reading websites.

 

However what about this site here.

 

Or maybe I should just give up.

 

I'll get my crimper

 

PN

 

YAY 50 Posts finally :D

[TomLyall]

ah we all make mistakes and learn something new every day, I'd like to think im the first to admit that im far from perfect, however I do have a horrible habit of always thinking im right...:S

[Madmac]

er, now my turn to be pedantic.... 100 base ethernet will use all 4 pairs, 10 base uses 2

 

(brings back horrible memories of replacing in excess of 200 rj45's cus someone was told only to crimp two pairs...)

 

Tom

 

both 10baseT and 100baseT use 2 pairs The Power Over Ethernet spec allows the other 2 pairs to be used to carry power to remote devices (not recommended as not upgradeable ) . Also used in some Artnet adaptors for remote power.

 

1000baseT (or G)ethernet uses all 4 pairs

[TomLyall]

hmmm, I would argue to the grave that its 4, but you seem to know what you quoting, although that doesnt mean im giving up...

 

im still really really sure that full duplex 100baset ethernet uses all four pairs of utp,

 

[edit] bit of reading... your right, 100base-tX requires 2, 100base-t4 utilises all four, allowing the data to be 'spread' out among the data lines.

[peternewman]

My question to you Tom would be why do you need the third and forth pairs, what would be sent down them. You already have one pair for transmitting and one for recieving so why would you need a third and forth pair.

 

WHOA!!!

I have conclusive proof that 10/100 only needs 2 pairs:

The Proof

Notice how it says

They are only appropriate if, to transmit data, 2 pairs are required.

And

Cat5 10/100 Economiser

 

So there you go, this also seems to confim that 1000 needs all 4 pairs.

 

PN

[TomLyall]

on a slightly different point, is that product not just a simple splitter, sortof ripping people off a bit...

 

[edit]

[newline][/newline]Standard        Cable Type                            Pairs/Strands Needed [newline][/newline]100BaseT4     Category 3, 4, or 5 UTP           4 pairs [newline][/newline]100BaseVG     UTP Category 3, 4, or 5 UTP    4 pairs [newline][/newline]100BaseVG     STP 150 Ohm STP                  2 pairs [newline][/newline]100BaseTx     Category 5 UTP                      2 pairs[newline][/newline]

[peternewman]

on a slightly different point, is that product not just a simple splitter, sortof ripping people off a bit...

 

Do you mean cost wise. If so then yes, because with a bit of simple planning you could wire the one cable straight into the back of a double socket. I suppose its a case of paying for an easy solution. I don't know if that is a particularly cheap model, just the first one I found when I googled for them having remembered about them. They are quite a clever idea I think.

 

100BaseTx, Category 5 UTP, 2 pairs

 

You have just disproved yourself . Well certainly whenever I have networked things I have connected as Tx.

 

PN

[TomLyall]

'You have just disproved yourself '

 

yes I know, I was planning to...

 

ill get my humble pie....

[peternewman]

I am intrigued though, what do the other 2 suffixes T4 and VG mean?

 

PN

[TomLyall]

not quite sure about the VG but the T4 is simply because it uses all four pairs

 

to the mods: sorry about the 13 or so off topic posts...

[gareth]

Moderation, 12/4/04, 14:45 - the above posts split from "Homemade DMX Cables" in the Lighting forum.

[Matt]

some 10base based network systems in offices have the telephone line running through the same cable, saving space and possibly time, I thought telephone system only uses 1 pair though not 2?