Question Curious Ethernet Situation

[BGJessica]

I'm having an incredibly curious ethernet situation.

Context:
My home has two internet jacks. Jack 1 is in the kitchen, Jack 2 is in the office room. My router is right next to Jack 1. My computer is near Jack 2.

My current internet setup:
Jack 1: Internet comes into the unit from Jack 1 -> into my router (for wireless) -> ethernet from router back into the wall using ethernet cable A (to provide network connection to Jack 2)
Jack 2: Ethernet using ethernet cable B from wall -> into my computer

Today, I switched cable B to a new ethernet cable (cable C). My ethernet is now connecting and disconnecting every 2 seconds constantly.

Cable B is a standard 7 foot CAT6 ethernet cable. Cable C is a standard 50 ft CAT6 ethernet cable (specifically the QVS CAT6/RJ45 Ethernet Patch Cord purchased from Microcenter)

Things I have tried:
1. Wireless network is working perfectly fine as it always has. (Rules out the router being the issue)
2. I have tried testing cable B again and it works fine. (Rules out Jack 2 being the issue)
2. I have connected cable C directly from the router to my computer and it also works fine. (Rules out cable C being the issue)
3. I have called my ISP and they said that everything looks fine on their end.

I am now encountering a paradox where I have ruled out each individual component as the issue.

My question is: is it possible that somehow Jack 2 is incompatible with cable C but compatible with cable B?

Any insight/advice would be appreciated.

 

[bill001g]

Cables are really strange and there is no way to really test them without meters that a home user can not afford. The cheap testers generally only find simple problems.

The longer the cable the more a small defect can cause issues.

I assume what you call jack 1 actually has 2 ports since somehow you connect the router wan port to something that gets internet and a second one hooks a lan port to go to your computer. If it is a coax cable and a ethernet port then that would explain it.

How does the wire that is in the wall go between jack 1 and jack 2. Is this a direct connection between the 2 or does this go to some kind of central room that the cable somehow are connected together either directly or with a switch.

I agree is it not likely your new 50ft cable since it appears to be a quality cable. Microcenter along with most other vendor sell that trash flat cable but the QVS ones tend to be their quality cables.

It depends on how exactly the connection between the 2 jacks works. In the simplest method it appears as some ethernet couplers that you would use to make a ethernet cable longer. As long as the distance in the wall + your 50ft is less than 100 meters it will be good. It is highly unlikely that you have another 250ft of cable in the wall but the wall jacks themselves introduce resistance so your distance is less.

I would first pull the plates on both ends and do a simple inspection of the wires. It likely will look fine but maybe you get lucky and find a loose wire or find that the wire colors on both end do not match one of the proper pattern.
Generally you need a punch down tool to get the wires connected but you can use a tiny screw driver if you are very careful. You could pull the wire out cut a tiny bit off and repunch them down.

Microcenter sells cheap punch down tools for about $3. You need a 110 style one for ethernet. If you are going to go all the way to microcenter you might as well pick up new keystones just in case. You can also get what are called tooless keystones but I don't think microcenter sells them I have seen them at stores similar to home depot.

This is purely guess work though. Without a almost $1000 meter you blindly replace keystones and wires and hope to get lucky.

It only takes a small amount of corrosion on one wire in a jack or one slightly loose connection to cause issues.

 

[BGJessica]

Cables are really strange and there is no way to really test them without meters that a home user can not afford. The cheap testers generally only find simple problems.

The longer the cable the more a small defect can cause issues.

I assume what you call jack 1 actually has 2 ports since somehow you connect the router wan port to something that gets internet and a second one hooks a lan port to go to your computer. If it is a coax cable and a ethernet port then that would explain it.

How does the wire that is in the wall go between jack 1 and jack 2. Is this a direct connection between the 2 or does this go to some kind of central room that the cable somehow are connected together either directly or with a switch.

I agree is it not likely your new 50ft cable since it appears to be a quality cable. Microcenter along with most other vendor sell that trash flat cable but the QVS ones tend to be their quality cables.

It depends on how exactly the connection between the 2 jacks works. In the simplest method it appears as some ethernet couplers that you would use to make a ethernet cable longer. As long as the distance in the wall + your 50ft is less than 100 meters it will be good. It is highly unlikely that you have another 250ft of cable in the wall but the wall jacks themselves introduce resistance so your distance is less.

I would first pull the plates on both ends and do a simple inspection of the wires. It likely will look fine but maybe you get lucky and find a loose wire or find that the wire colors on both end do not match one of the proper pattern.
Generally you need a punch down tool to get the wires connected but you can use a tiny screw driver if you are very careful. You could pull the wire out cut a tiny bit off and repunch them down.

Microcenter sells cheap punch down tools for about $3. You need a 110 style one for ethernet. If you are going to go all the way to microcenter you might as well pick up new keystones just in case. You can also get what are called tooless keystones but I don't think microcenter sells them I have seen them at stores similar to home depot.

This is purely guess work though. Without a almost $1000 meter you blindly replace keystones and wires and hope to get lucky.

It only takes a small amount of corrosion on one wire in a jack or one slightly loose connection to cause issues.

That is absolutely correct about Jack 1. It has two ports, one of them supplies internet to the router and then the other one receives internet from the router to transmit to jack 2 through some internal wiring.

Because I live in an apartment building, I am not sure of how the internal wiring between jack 1 and jack 2 is oriented. But it seems possible that the distance is > 50 ft (therefore > 100 ft with my 50 ft ethernet cable) just based on the distance between the two jacks. Could this be a cause of the inability to transmit a constant internet connection through jack 2?

 

[baboma]

@op, you are overthinking it. Old setup works fine; new cable causes problem. Solution: Exchange cable for a different brand. Better yet, get 2-3 cables of different brands, as then you have several to test against.

Now, if all of the new cables fail, then you can get your hands dirty.

Rule one of troubleshooting: Try the simplest/cheapest solution first. KISS.

PS: Do not do the below unless warranted, ie after trying other solutions first. Taking apart a working setup just to "see what's going on" is almost always bad advice. You can make things worse.

>I would first pull the plates on both ends and do a simple inspection of the wires...

PPS:

>Cable B is a standard 7 foot CAT6 ethernet cable. Cable C is a standard 50 ft CAT6 ethernet cable

One obvious possibility is the length of the new cable. While max length of Cat5e/6 is 328', you have no idea of the quality of Cat wiring within the walls, or what their existing lengths are. It may well be that the wiring is marginal enough to work with a 7' cord, but not a 50' one.

Since it's an apartment, you have no recourse to upgrading the wiring in the wall. You just have to find a workaround. Search on Ethernet repeater. Alternatively, add a switch which also repeats the signal. Or more simply, get a cable shorter than 50' (do you actually need 50'?)

To revise my first suggestion: Get several cables of different lengths, and try them out.

 

[bill001g]

That is absolutely correct about Jack 1. It has two ports, one of them supplies internet to the router and then the other one receives internet from the router to transmit to jack 2 through some internal wiring.

Because I live in an apartment building, I am not sure of how the internal wiring between jack 1 and jack 2 is oriented. But it seems possible that the distance is > 50 ft (therefore > 100 ft with my 50 ft ethernet cable) just based on the distance between the two jacks. Could this be a cause of the inability to transmit a constant internet connection through jack 2?

Even 100ft is well below the 100 meter limit. It should work fine.

When you live in apartments it is a pain because even when you can you should not mess with the wall jacks. In addition the apartment maintenance guys will have no skills like this, they can fix a sink or change a filter but unlikely they have never even looked at ethernet jacks.
Not sure what to recommend. Because your cable works directly to the router it is likely the cable is fine.