How to know if Ethernet Port or Cable is broken?

[Zaughtilo]

I usually use WiFi, but today I wanted to start going wired. So I find an old Ethernet cable from the box of a router I used 6 years ago, plug it in like it should be, one end laptop, one end router. But when I go to Network Connections, it says there is no cable plugged in, and when doing a internet speed test, results are the same as when I am using WiFi.
After doing some research, I now know it is one of two things, either the port on my laptop is broken, or the cable is broken. Seeing as the cable is 6 years old, and that I've read that these cords typically break over time, I suspect it is that. But I don't want to drive all the way out to the local Bestbuy to get a new Ethernet only to have to go back to get a USB-Ethernet adapter.
I've gone into device manager and updated all the drivers, restarted laptop, blah blah. Nothing worked.
But I would like to save twenty bucks If I could. So how do I figure out if the Ethernet port on my laptop, or the cable itself is broken?

 

[geofelt]

First of all, make certain that the Ethernet cable is fully plugged in to the laptop port.
On mine, you have to push it in very firmly.

In device manager, properties for the adapter should say if it is working or not.
If you see a yellow ! look to a different driver.

If you get connection, you will see a led on the end blink.

When testing, turn off the wifi to be certain you are testing Ethernet.

I really doubt that your cable is bad so check other possibilities first.

 

[InvalidError]

You should be able to find ethernet cables just about anywhere and you likely have more than one already since whatever broadband modem/router your ISP provided must have had one too, so you can test your laptop's port using that.

Cables don't usually go bad unless they suffer some degree of mechanical abuse. Most of my cables are ~15 years old and still working perfectly fine apart from broken retention tabs.

 

[Zaughtilo]

First of all, make certain that the Ethernet cable is fully plugged in to the laptop port.
On mine, you have to push it in very firmly.

In device manager, properties for the adapter should say if it is working or not.
If you see a yellow ! look to a different driver.

If you get connection, you will see a led on the end blink.

When testing, turn off the wifi to be certain you are testing Ethernet.

I really doubt that your cable is bad so check other possibilities first.

In device manager it says my ethernet card is working fine.
I am sure it was plugged in on both sides.
There is no LED blinking on the ethernet when I plug it in.
Nothing changed when turning off the wifi first.

So you think it's the port on my laptop?

 

[bill001g]

It is not common for either the port or the cable to break. A bad cable though is a much more likely. I would still try the cable first. You should be able to get cables from pretty much any store if bestbuy is far away. The sell them in grocery stores even.

There is no way by looking at a cable to tell if it is good or not...unless it is badly damaged. There are expensive certification meters that can test cable but they cost close to $1000.

 

[jsmithepa]

Seeing as the cable is 6 years old, and that I've read that these cords typically break over time, I suspect it is that.

I've been doing this for years, make it decades and I don't know from what obscure part of Internet you got this information. 99.9% cable is OK.

How do you know? very simple really, if laptop says UNPLUGGED then you don't have a connection, and this can also be verified by the tinny LED by the RJ45. So OK, some laptops may not have LEDs but certainly the RJ45 by the switch port have LEDs?

Surely, there is ANOTHER device you can try. TV? DVD player with network? SOMETHING. RJ45 to RJ45, the LEDs should light up.

 

[Zaughtilo]

I don't remember where I got the information. Either way, I still need to get a new, longer cord because the one I have is like 4 feet long, at this point I am just trying to figure out if I need a USB-Ethernet adapter or not. When I get home I'll try to connect it to my smart TV to see if the LEDs come on, and I just now remembered where I might have another Ethernet cable, so I'll see if that one yields any different results. I get home in about 8 hours, I'll report my results then.

 

[Zaughtilo]

Just got home and tried the things I said. Connecting a different Ethernet cable to my laptop still resulted in it saying that there is no cable connected. So now know that is my laptop Ethernet port ("realtek pcie gbe family controller #2" is working properly), I have found and picked out a USB-Ethernet adapter. When connecting the Ethernet to my TV, the LED on the router came on. So that question is settled, cable is fine, but need an adapter.

One question I do have now, though, is how, if possible, would I convert a phone wall jack to be an Ethernet port? I haven't been able to find any adapters online clearly showing that they do this. I ask this because there is a unused phone jack in this room. It looks like an Ethernet port so I got all excited when remembering it's existance, only to get bummed when did didn't fit.

 

[bill001g]

You pretty much must replace the jack with a ethernet jack. Still it must have actual ethernet cable in the wall, you can not use the old red,yellow,green.black stuff. It also has to run back to a common area it can not be daisy chained jack to jack.

 

[Zaughtilo]

You pretty much must replace the jack with a ethernet jack. Still it must have actual ethernet cable in the wall, you can not use the old red,yellow,green.black stuff. It also has to run back to a common area it can not be daisy chained jack to jack.

This house is 20 years old and behind the phone jack were the red, yellow, green and black wires. Rip.

 

[Zaughtilo]

I did my best to read what is written on the wire, it is written in dots and kind of hard to understand. This is what I got, some could be wrong. "EJD3J85 I UL 3 TYPE MPR OR CMR 22 AMO". Has the red, yellow, green, black wires coming out of it. Guessing it can't be used for Ethernet?

 

[InvalidError]

This is what I got, some could be wrong. "EJD3J85 I UL 3 TYPE MPR OR CMR 22 AMO". Has the red, yellow, green, black wires coming out of it. Guessing it can't be used for Ethernet?

That's plain phone wiring. Category 5 unshielded twisted pair wiring (the minimum officially required for 100Base-TX and beyond) would have four pairs with orange, green, brown and blue where the complement of each wire is white with a matching color stripe. If you look at the end of an Ethernet/RJ45 patch cable, you should be able to see the different wire colors through the transparent connector.