I have some cat5 cables in my attic in need to splice . they have been up there for 10 to 15years so no sure if cat5e or cat5.

I'm looking at a tool-less connector on amazon, but the color coding has a orange-green line I do not see in my cable

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    Note the faint text on the outer jacket of the cable. Examine that carefully and it will tell you (generally repeating every 2 or 3 feet) exactly what type of cable it is.) – Ecnerwal Apr 1 '19 at 18:34

That's not "orange/green", it is T568A vs. T568B

Cat 3/5/6 cabling can be connected in two "flavors" - T568A and T568B. The cable (without ends attached) is the same and they are functionally identical. The only question is the sequence - Blue/Orange/Green/Brown vs. Blue/Green/Orange/Brown. Most connectors & jacks include color-coding for both types, marked "A" and "B", so that you can mix & match parts from different brands and have everything work together. You can actually see that in the image if you look closely - A and B are printed on top of the color coding on both left (solid blue, pin 4) and right (brown/white, pin 7). If your device says "Cable should be T586A CAT 5" and you wire it up T586B CAT 5e, it will work just fine, because the electrons don't care about the insulation color.

I usually use T568B, but it really doesn't matter as long as you are consistent - i.e., both ends of each cable should (normally) be the same.

What does matter is the quality of the connection.

Each new cable type 3 -> 5 -> 5e -> 6 puts in new, more exacting requirements on the number of twists and other factors. So make sure any connectors, adapters, splices, etc. meet the requirements of the cable type you want to use. If you have Cat 6 everywhere except one segment is Cat 5e then you'll be fine with Cat 5e speeds but Cat 6 might not work, and you may have trouble figuring out why things aren't working right. So I would at a minimum use the same quality/specification for everything that is hidden - wall jacks, cable inside walls, splices in the attic, etc.

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    use T568B, +1, because it "matches the older ATA&T 258A color code and is/was(?) the most widely used wiring scheme." – Mazura Apr 1 '19 at 23:22
  • It's also worth noting that Cat 3 only has 3 pairs of cables, and is almost always used for telephone wiring (you can cheat and use it as data-only Ethernet, since the data part needs only 4 wires, but it's poorly shielded for data compared to Cat 5 or higher) – Machavity Apr 2 '19 at 0:44
  • @Machavity Sorry to be blunt but: wrong! Cat 3 normally has 4 pair, just different specs from Cat 5/5e/6. One big difference is that Cat 3 only actually used 2 pairs for Ethernet, so you could safely use the other 2 pairs for phone lines. With Gigabit Ethernet and often with Power Over Ethernet (i.e., even at 100 Meg.), all 4 pairs are used for Ethernet, so you can't share the cable with phone wiring. Cat 3 was totally standard for 10 Meg. Ethernet. The differences also are NOT shielding - typical Cat 3/5/5e (and even often Cat 6) do not have shielding, unlike RS232 and other cabling.. – manassehkatz-Reinstate Monica Apr 2 '19 at 0:59
  • schemes. But Cat 3 is not rated - and not reliable - for 100 Meg. and above due to other design factors. – manassehkatz-Reinstate Monica Apr 2 '19 at 1:00

What's confusing you here is that the connector is doing some wire-shifting for you to make it easier to make your connection. I've never seen blue wires used for the first pair (normally the blue wires are pins 4 and 5 because you can use RJ-11 phone connectors with RJ-45 ethernet jacks and that setup is backwards compatible). You can see the pin numbers at the bottom of their color code. Normal Ethernet uses pins 1,2,3 and 6.

As mentioned in comments, B (where Orange is on pins 1 and 2) is the more common. You can pick A (Green on 1 and 2) if you so desire, but be consistent or you'll create a crossover cable (which is used to connect two computers together directly, instead of through a switch, and is almost certainly not what you want).

  • Actually, if you look at the connector (I know, the OPs picture is fuzzy - I'll try and add a better one), blue is pins 4 & 5 (note in my answer about "solid blue, pin 4"). The connector is not doing "wire shifting". Every connector has its own scheme, the only rule is that each pair of wires (e.g., blue, blue/white) should be together. But the arrangement of the pairs varies quite a bit - some have all 4 side by side (like the OPs picture), some have two pairs on each side facing each other, etc. – manassehkatz-Reinstate Monica Apr 2 '19 at 1:03

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