Replaced my router and did not work. After some head scratching, noticed the connection from the modem to the 'internet' port at the router had different pinout on the new supplied cable. Changed the cable and works.
Is there no standards for that modem-to-router link ?

 

Replaced my router and did not work. After some head scratching, noticed the connection from the modem to the 'internet' port at the router had different pinout on the new supplied cable. Changed the cable and works.
Is there no standards for that modem-to-router link ?

It's possible you ran into a crossover cable. These were common years ago for connecting two computers to form an ad hoc network, for instance, and other applications. Modern equipment doesn't require a crossover cable and somehow adjusts internally.

 

EIA/TIA 568A and 568B

 

Thank you.
Is there 3 kinds of 'standard' wiring for each 568A and 568B? Straight, rollover and crossover?

----> https://www.computercablestore.com/straight-through-crossover-and-rollover-wiring

 

Thank you.
Is there 3 kinds of 'standard' wiring for each 568A and 568B? Straight, rollover and crossover?

----> https://www.computercablestore.com/straight-through-crossover-and-rollover-wiring

No..
Cross-over is really just 568A on one side and 568B on the other..
Rollover is pretty exotic AFAIK..

 

As long as both ends are the same (A or B), then it really doesn't matter. But if the ends are different then it's most likely a crossover cable as described above.

 

No..
Cross-over is really just 568A on one side and 568B on the other..
Rollover is pretty exotic AFAIK..

After all these years I'm surprised. I would have sworn that a crossover cable was the same thing that's called a rollover. I must have never tried to make a crossover cable, because it wouldn't have worked.

 

In post #4, their "crossover cable" is incorrect. the correct form is here: https://en.wikipedia.org/wiki/Ethernet_crossover_cable

Two pairs are crossed and 1 pair is uncrossed in a "crossover cable".

Gigabit is by definition Auto-MIDX so it usually doesn't matter if it's made wrong. I believe the performance is better when it's made the correct way.

You use to need a crossover cable when connecting say a laptop to a device without a switch or hub, Old hubs had UPLINK ports which were just a shared port wired in the crossover configuration. 10baseT and 100baseT only use 2 pairs. POE (Power Over Ethernet) adds way to many extra complications. Doing it over 4 wires or 2 pr requires some thought.

"Rollover" cables are commonly used for telco. The wall to phone cord is a rollover cable.

 

What still amazes/confuses me is that why was there a need to swap some of the color pairs in the first place..
If you start with stripe orange then solid orange, why didn't they just continue that with stripe green, solid green, strip blue, solid blue, stripe brown, solid brown..
It doesn't matter and just makes it easier for a person to remember vs having to remember to swap solid blue and solid green in the logical pattern..

Or are there certain types of data that are color blind or maybe fashion/color conscious and just straight up refuse to travel down a solid blue wire ? Damn racist data

Ok..ok.. I'm sure its some cross-talk cancellation or some impedance thing but darn it all why not just make the cables twisted properly so we just need to keep the easier to remember color scheme.. This stuff is just boring unless you can throw in some attempt at humor thinking about color bias in data pairs..

 

Some of us know that electrons are color blind.

I'll use these two links to try to explain stuff.

https://en.wikipedia.org/wiki/TIA/EIA-568
https://tombuildsstuff.blogspot.com/2015/01/rj11-phone-to-rj45-jack.html

Before there was data, there was the USOC standard. Before that modular jacks, quad wire and princess phones ans even something called ground start. You had ground, a voltage and the telco line for the lighted dial princess phone.

The modular jack came around and the USOC standard was adopted. This used the inner most pair for line #1 and essentially fanned out until the outer most pair was used for line #4.

Then data came along and guess what? That large separation distances of the were not good for data.

Then there was the 25 pair cable standard that's been around for eons. https://en.wikipedia.org/wiki/25-pair_color_code

What you want in the end is maximum compatability.

Two lines of the USOC code matches the TIA-568A when only 2 pairs are used. They share the same colors and are even twisted right. It even matches the 25 pin pinout when 2 lines are used.

So, to really only wire one way, you want to use the TIA568A standard.

The 6 pin modular connectors will fit the 8 pin jacks, but your much better off to use a sleave.

10-baseT Ethernet, I think uses a wierd pin configuration because both single line telco RJ45 and 10baseT Ethernet won't interfere with each other.

The important thing is that the wires stay paired in 568A and 568B standards. Only the colors change.

For 4 lines or more, you definately have to do something different.

Here https://www.amazon.com/URBEST-Female-Telephone-Ethernet-Adapter/dp/B00RX8I0PY is a prime reason why I hate Amazon.
1st question: Is this a one, two, three or 4 line adapter?

The picture suggest a 2 line adapter. Is that then two lines on each 6P4C or two separate lines

The picture they don;t include (the one with the diagram on the part), I think, would offer some insight,

the picture suggests that it uses 4 wires on the RJ45 end and 4 on the RJ11 end and it could be replaced by this http://www.l-com.com/ethernet-modular-8x8-insert-adapter-pkg-10 $0.40 part.