When is cat5 cable not cat5 cable?

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Rikkitic

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#151679 1-Sep-2014 20:22

I bought some cheap cat5 cable off Trade Me to run a wired link from my desktop to my gateway. The trader claimed it was better quality (than the competition) but I chose it because it was cheap.

I opened the cable to extract a couple unused wires for a telephone connection and hooked everything up. It all seems to be working fine (100 Mbps, no discernable cross-talk) and I have no complaints, but I do have a question. When I opened the cable I noticed that it wasn’t shielded and I don’t think the wire pairs were even twisted, though now I am not so certain. Then I bought some ‘telephone’ cable that turned out to contain six pairs that are twisted. As far as I can see there is little or no difference between the cables, except the colour (cat5 is blue).

I am no expert so my question is, what is the difference? What makes one cable cat5 Ethernet and the other only telephone if both contain six cores, maybe or maybe not are twisted, and have no shielding? Is my blue cat5 cable not so superior after all, but I just got lucky that it works without interference?

Plesse igmore amd axxept applogies in adbance fir anu typos

gregmcc

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#1119940 1-Sep-2014 20:40

cat5 contain 8 cores, not 6, cat5 is not by default sheilded (UTP) unshielded twisted pair, (STP) shielded twisted pair is the one you are thinking of, mostly used where there is a risk of electrical interference.

Telephone wire is usually 6 core, but most modern installs just use cat5 so it can be used for either phone or data.

If 6 core cable is been sold as cat5 then someone is not telling the truth

RunningMan

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#1119958 1-Sep-2014 21:00

Picture?

richms

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#1119961 1-Sep-2014 21:05

Umm, you bought the cheapest product with unregulated specifications from trademe and are suprised that it might not be actual cat5 cable?

Richard rich.ms

Rikkitic

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#1120042 1-Sep-2014 22:12

richms: Umm, you bought the cheapest product with unregulated specifications from trademe and are suprised that it might not be actual cat5 cable?

Not really surprised, just curious about the difference. Like I said, it all seems to be working fine so no issues there. And I must be mistaken about the cat5 being only 6-core. That is how I remember it but it must be 8. As I said, I'm not an expert and I forget what the specification is for 100 Mbps, which is what I am getting. Sorry, no photo. It is all installed and that would be difficult.

Even if it is in fact 8-core, though, I'm pretty sure only 4 (6 at the most) are needed for a 100 Mbps connection. So my question remains. If the cat5 cable is not shielded, and the phone cable has twisted pairs, assuming 6 cores is in fact enough for a 100 Mbps link, what is the difference if any between using the phone cable for this instead of cat5?

Plesse igmore amd axxept applogies in adbance fir anu typos

richms

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#1120047 1-Sep-2014 22:16

Twist rate will vary between phone cable and cat5, and I think phone cable doesnt have carefully controlled insulation thickness to create a ballanced transmission line with a known impedance. Then again, cheap cat5 probably doesnt either.

I have run 100 meg ethernet over a piece of the old 2 pair homelan cable quite sucessfully even tho it is only cat3 rated and therefore only good enough in theory for 10 meg. Things would change if it was bundled up with other cables with the resulting crosstalk between them.

Richard rich.ms

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#1120066 1-Sep-2014 22:24

If all you are ever going to want it 10/100, not much. Twisted pair is twisted pair I would think. As long as the wire gauge is the same, it will work in an RJ45 connector. Should you do it? I still wouldn't. If you put a better router/switch in later that is gig, you will have to run it all again. Do it right, do it once.

Try Vultr using this link and get us both some credit:

http://www.vultr.com/?ref=7033587-3B

Rikkitic

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#1120095 1-Sep-2014 22:42

Thanks for the excellent responses. You have answered my question and I appreciate it. This gives me good insight into the actual differences and the consequences of cutting corners. This is the kind of clear information I was hoping for.

Plesse igmore amd axxept applogies in adbance fir anu typos

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Bung

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#1120121 1-Sep-2014 23:26

The original 2 pair cable that replaced 6 wire as telephone cable was made with the same twisted pairs that went into the manufacturer's data cable ie it was half the data cable.
edit note that it was definitely twisted pairs used.

InstallerUFB

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#1120190 2-Sep-2014 06:58

Simply

Cat5 UTP has 8 copper cores twisted into 4 sets and was designed for 10/100 and will do 1G on short distances

Cat5e UTP has similar cores but a differnce twist rate (better balance etc) and was designed for 1G and below (Homelan Phone cable is = to half this cable)

Cat6 UTP has bigger cores and a central seperation core to hold the 4 sets in a set position and is designed for 10G (with the correct installation) and below