A faulty (cheap) Ethernet adapter

In short: a faulty USB Ethernet extension caused the wired internet to stop randomly anywhere between a few minutes to 30. Solution was to order a better quality of USB Ethernet extansion.

Someone was looking for a computer / IT technician on Facebook with an Internet connection problem. I contacted him over chat and I asked him relevant questions about the symptoms and about the equipment he had. His answers were helpful.

After arriving to the Customer’s house, I discovered that the wifi works perfectly, but the wired connection cuts out after a few minutes. He used a few Eero 6 around the house to extend the wifi signal.

There was a USB-A device connected to the Macbook Pro M3 adding few extra USB-A ports and an Ethernet port to the Macbook as it doesn’t have those ports. Mac’s are reliably boxes, I had no doubt that the box itself has no problem. The cable was the highest quality CAT 8 cable, so no problem there either. I didn’t even bother testing the cable, because for the short time it worked, it worked perfectly. Contac problems have different symptoms. 

So I started to play with the device. After some time, I found that if I unplug it and plug it back in, the internet connection comes back for a short time. Every time.
Customer was running a web based desktop on this 3 extended screens. Somehow I managed to crash that desktop app. Now the internet connection lasted longer. Interesting. So it seemed that if the load is small the internet connection lasts longer.

I was trying to change some settings on the physical Ethernet port in the Mac settings, but they didn’t “stick”. That was unusual also. Clicking the Save button and it acts like it worked, but after a refresh all numbers are the old numbers. This was a dead end.

Any time I switched over to the wifi, it worked flawlessly (but only 0.3 Gigabit/sec). Customer really wanted to benefit from the almost 1 Mbit/sec that the cable connection provided.

I was suspicious that the device is not the best quality. If it was cheap they didn’t equip it with a fast chip. It also seemed that the longer I use the internet the longer the connection lasted. After an hour or so, I was able to play a 4K video on Youtube for over 30 min.

Finally I looked up another Ethernet device on amazon for some 10 euro and told the Customer to order it. Since it was only an Ethernet device and nothing else (no additional USB-A ports on the device) it should work well. And than if it does work well, we will know this was the problem.

Lo and behold Customer told me a few days later that his wired internet works perfectly at 0.9 Gigabit/sec. Now he bought the device that had the extra USB-A ports also, but it was a high quality make.

(The adapter shown on the photo is not the faulty part.)