Ethernet cablecrimping questions

[Indian pc builder]

Ok, So I have a ethernet cable that I crimped myself and I was not able to get the exact order that It is supposed to be in, however, since technically just making sure that all the cables are connected to the same pins on both sides of the connection should work, that is what I did, however now my truenas scale server connected to these pins is only reading them as a 100baseT connection and not ad a gigabit connection, despite, the switch, router , and everything else being gigabit. any help on how to fix this? I did use a cable tester and all the pairs do work, also I tried the cable on a different computer, and that too picked it up as 100base t.

 

[Needfuldoer]

6 minutes ago, Indian pc builder said:

Ok, So I have a ethernet cable that I crimped myself and I was not able to get the exact order that It is supposed to be in, however, since technically just making sure that all the cables are connected to the same pins on both sides of the connection should work, that is what I did, however now my truenas scale server connected to these pins is only reading them as a 100baseT connection and not ad a gigabit connection, despite, the switch, router , and everything else being gigabit. any help on how to fix this?

 

Re-terminate the cable properly.

 

Ethernet uses balanced signals on the different pairs of wires, so putting the correct ones together absolutely does matter if you want the cable to perform as it should.

[Skipple]

Snip snap. Cut the cable and re-terminate. There's more than likely more wrong with it such as a missing cable or two. 

[Indian pc builder]

Just now, Needfuldoer said:

Re-terminate the cable properly.

yeah, i realised that as i edited this post

[Indian pc builder]

15 minutes ago, Skipple said:

Snip snap. Cut the cable and re-terminate. There's more than likely more wrong with it such as a missing cable or two. 

I did use a cable tester and everything works fine, so i have no idea why it shouldn't work, but apparently it does not

 

[Needfuldoer]

17 minutes ago, Indian pc builder said:

I did use a cable tester and everything works fine, so i have no idea why it shouldn't work, but apparently it does not

 

The pairs have to match because that's how differential signaling works. A "cable tester" that just blinks lights won't tell you if a cable passes spec, only if the correct pins have continuity on each side.

 

Pick one of these standards and stick with it:

 

 

[Indian pc builder]

1 hour ago, Needfuldoer said:

The pairs have to match because that's how differential signaling works. A "cable tester" that just blinks lights won't tell you if a cable passes spec, only if the correct pins have continuity on each side.

 

Pick one of these standards and stick with it:

 

 

welp, my bad for not looking deeper into the physics of signalling

[Skipple]

11 minutes ago, Indian pc builder said:

welp, my bad for not looking deeper into the physics of signalling

technically the cable should work fine, as long as the crossed wire is crossed in the same way on either end. A will still get to A and B will still get to B. 

Advice remains: re-terminate using appropriate 568B

[Indian pc builder]

48 minutes ago, Skipple said:

technically the cable should work fine, as long as the crossed wire is crossed in the same way on either end. A will still get to A and B will still get to B. 

Advice remains: re-terminate using appropriate 568B

no, i didn't actually open up a pair, i just put them sequentially next to each of their pairs

[mariushm]

original 100 mbps used positions 1 and 2 for one pair  and  positions 3 and 6 for the other pair.  one pair is receive, the other is transmit.  that's the reason for those two wire orders t568-a and t568b - when you make a cable with a at one end and b at the other, you made a 100mbps crossover cable, allowing two computers to talk to each other without a hub or switch (tx goes into other pc's rx, and same from the other end) you make a circle between computers)

 

The middle wires (4 and 5) were sometimes used for phone line to save installing separate phone cable and later it was also used for passive power over ethernet.

 

Gigabit uses the other two pairs as well, so it's important to have the wires arranged correctly. it won't work if one of the pairs is installed wrong.

 

for cables above cat5e, the pairs are even separated physically along the cable with a plastic + shaped thing.

 

on gigabit you cant (should not) use cables with those two pairs twisted - gigabit cards have auto pair detection and there's no need. also proper crossover for gigabit would need to have all four pairs flipped not just two.