does coupler degrade performance?

[yogurtboy]

rather than getting a 25' cable, i've got a very specific situation where i'd rather use a 5' cable coupled to a 20' cable [long story]

will the coupler degrade performance?

in other words, will a 25' cable provide better performance than a 20' cable coupled to a 5' cable?

thx

 

[network-lab]

will the coupler degrade performance?

No, it shouldn't be a problem.

Mirko

 

[blue68f100]

All connections degrade the signal.

But your distance is to short for any problems to show up.

 

[ypfamily]

Hi,

I have a similar question, but I'd like to give a bit more detail and see what everyone thinks about this scenario.

I have a 2 story house with an attic and a basement. Attic is not finished, but has insulation which lays on top of the 2nd floor ceiling. One of the data ports on the 2nd floor was looped by mistake to a different room instead of being home run.

There are all kinds of difficulties in home running it now since the wall has insulation and it's close to the slope of the roof and so on. It's possible, but very difficult. So, the installer offered a compromise: He will home run the wire through the conduit pipe to the basement, but instead of feeding it through the wall, he will cut the existing looped wire and put a coupler in.

So, the configuration will be:
From cable modem in basement - to switch in basement - to port in wall on second floor - to wireless router/switch - back to another port in that same wall which is now looped but will be home run through the coupler - back to the switch - to all other ports in the house.

Will the coupler degrade performance? I would guess that from the outlet port in the wall to the coupler it will be about 8-9 feet and from the coupler back to the switch in the basement probably around 70-90 feet.

Also, will the fact that it will be sitting the attic be a problem? It's not conditioned, so moisture is there to a degree, I assume. Obviously, it gets crazy hot up there in the summer time.

Any suggestions? Should I make the installer home run the whole thing or is what he is proposing good enough and won't really be a problem?

Thanks,
Yaakov.

 

[Darth_Indy]

The Ethernet spec says cable runs of 100 meters is minimum to be IEEE compliant so 90 feet is no problem unless the coupler is bad.

The the temperature changes in your attic will change the attenuation in the wire but with only 90 feet total run, you should have plenty of extra margin and will be okay.

I'd be more concerned on the effect of moisture on the coupler, if it is exposed the connectors could oxidize enough that the connection could degrade enough to stop working. I've heard of this happening and the outward sign was that you couldn't establish a connection at 1G (best rate was 100Mb/s). This makes sense in that when the Ethernet PHY goes through autonegotiation it picks the best rate possible. That is, if it can't equalize the cable attenuation at 1G it steps down to a lower rate where there is greater margin of error and hense a better chance to get link. If you have a good quality of coupler and protect it carefully from moisture you'll probably be okay.

Good luck.

 

[El0him]

No.

rather than getting a 25' cable, i've got a very specific situation where i'd rather use a 5' cable coupled to a 20' cable [long story]

will the coupler degrade performance?

in other words, will a 25' cable provide better performance than a 20' cable coupled to a 5' cable?

thx

 

[ypfamily]

Thanks for the reply. I decided to go ahead and home run the wire. I am planning to run virtualization servers there and don't really want the chance that my network will downgrade to 100.

Thanks.

 

[knudsen]

Good choice. Their mistake; make 'em fix it right. I ain't the sharpest hammer in the box, but I will not use a coupler on my network *except* to extend to an individual PC. They DO attenuate signal. They DO pickup noise. They DO fail. And they are not twisted pair *or* shielded. Crack one open and look. In practice, usually OK on short runs, as others have said.

 

[v13]

A typical network cable installation consists of cables that terminate on patch panels, to which at least two other cables are connected to (one at each side). This means that for a typical cable run between two active devices you will have 2 such connections (one on each patch panel). Using one coupler is roughly the equivalent of having one patch panel, which is less than what you would have if your house was built with network wiring.

As such feel free to use the coupler or, if you have the option, put a network socket on each end and connect to that.