What to test after an ISP installs a fiber terminal

Your internet is connected after the installer leaves, but that does not tell you whether the new fiber terminal, router, and Wi-Fi are all working well. A fiber terminal, sometimes called an ONT, converts the fiber connection for your home network.

Run a few checks before you put everything back in its usual place. Compare a wired connection with Wi-Fi, check for brief dropouts, and keep the results so you can give your ISP useful details if something seems wrong.

Test the new fiber connection

Connect a computer to the router with an Ethernet cable, if possible. Pause downloads, cloud backups, streaming, and other activity using the internet. If the ISP has not finished activation or has asked you to wait, follow their instructions first.
Open the Speed Test and run a test over Ethernet. Note the download speed, upload speed, ping, and jitter. Run it again after a minute to see whether the results are similar.
Disconnect Ethernet and run the test over Wi-Fi from the same room as the router. Keep the computer in the same spot for each run. This comparison helps separate the fiber connection from Wi-Fi coverage or interference.
Check for short interruptions with Connection Stability. Let it run for a few minutes and note response time, jitter, lost requests, or dropouts.
Repeat a test later, such as during a busy evening. Keep the connection type and location consistent, and write down the time and results.

Do not unplug or bend the thin fiber cable to make a test. If your ISP specifically asks you to connect a computer directly to the fiber terminal, use their instructions. A direct connection may require ISP settings, and the router may be needed for your service to work.

What the results mean

Ethernet is fast and Wi-Fi is slower

The fiber service and router's wired connection are probably working, while the difference is likely in Wi-Fi coverage, interference, or the computer's wireless connection. A slower result in another room is not by itself evidence of a problem with the fiber line.

Ethernet and Wi-Fi are both consistently slow

First check that no other device is using a lot of bandwidth. If wired results remain well below the speed your plan promises, the issue could be the router, its connection to the terminal, or ISP activation and provisioning. Compare more than one run before drawing a conclusion. Speed tests exchange test data with a server, and results can vary with test conditions.

Speed looks good, but there are lost requests or dropouts

A single speed result measures performance during a short test. It can miss brief interruptions. If Connection Stability reports lost requests or dropouts, repeat it with other devices' internet activity paused. Note whether the problem occurs on Ethernet, Wi-Fi, or both.

Ping or jitter changes a lot between runs

Ping is the time it takes for a request to travel to a server and back. Jitter is variation in that time. Both can change when the network is busy, so compare results when the connection is otherwise idle. Unusually variable results across repeated wired tests are more useful to report than one high reading.

What to check if something is wrong

Pause other internet activity. Stop large downloads, video streams, and cloud syncing on all devices, then repeat the test. Background use can reduce available speed and make delays less consistent.
Check the cable and connection. Make sure the Ethernet cable clicks firmly into the router and computer. Try another cable and router port if you have them. Do not force a connector or handle the fiber end.
Check the computer's network connection. On Windows 11, open Settings › Network & internet › Ethernet and confirm Ethernet is connected. On macOS, open System Settings › Network and select the Ethernet adapter. If you are testing Wi-Fi, stay near the router and reconnect to your usual network.
Restart equipment in the ISP's order. If the connection remains poor, restart the router and fiber terminal only as the installer or ISP directs. Some services need the terminal to reconnect before the router, and repeated power cycling can delay a diagnosis.
Check the terminal's status indicators. Use the labels and instructions for your exact model. If an indicator shows an alarm or the terminal appears not to have completed activation, take a photo of the lights and contact your ISP rather than guessing what each light means.
Contact the ISP with comparable results. Share wired download and upload speeds, ping, the time of each test, and any stability dropouts. Say whether Wi-Fi results differ. Ask them to confirm activation and check the fiber connection and service provisioning.

When the installation may need attention

If the terminal repeatedly loses its connection, shows an alarm according to its own guide, or has a visibly loose or damaged cable, contact the ISP that installed it. Fiber equipment and the connection outside your home are usually their responsibility. Avoid opening the terminal, moving the fiber connector, or trying to repair the line yourself.

If wired speed is steady and close to the plan's expected performance but Wi-Fi is weak in some rooms, tell the ISP that distinction. It points to home Wi-Fi coverage rather than a fault with the fiber line, and may call for router placement or a coverage solution.

Why a direct terminal test can differ

The router does more than provide Wi-Fi. It may handle the login and network settings required by your ISP, and it shares the connection among your devices. Connecting a computer straight to the terminal can therefore fail or give a different result even when the service is working. Use Ethernet through the router for the first comparison, and only bypass the router when your ISP tells you exactly how.