Technicolor Modem Lights (Meanings & Fixes)

Technicolor Modem Lights

There are several Internet Service Providers (ISPs) that favor the Technicolor modem. Comcast, Cox, and Century Link are among these.

It’s a vote of confidence in a good product range, but even the best modems don’t always work as you want them to.

Understanding your Technicolor modem lights and what they’re telling you will help you troubleshoot at times like these. 

First, we’ll provide you with a summary of what the different Technicolor modem lights mean.

After that, we’ll look at what you can do if they’re indicating trouble. These tips and tricks may save you from having to contact your ISP for support when there are issues that you can easily fix yourself.

So, without further ado, let’s take a look at what those lights are trying to tell you. 

Technicolor Modem Lights: What They Mean

C2100T or C2100Z modem/router

Note: This information applies to the C2100T or C2100Z modem/router. If you have a different model, scroll down for the relevant info. 

First up, we have the power LED light. It’s the topmost indicator light on your modem.

  • Solid green power LED: Power is on. 
  • Power LED off: There is no power supply to your modem
  • Solid red power LED: Possible hardware or software failure – give it 10 minutes to see if it changes color before assuming the worst. 
  • Flashing green or orange: A firmware test is in progress. The light should change color in a few minutes. 

Next, let’s look at the DSL light. It’s the light just below the power LED light.

  • DSL light is solid green: You are connected to a DSL network.
  • DSL light is off: You are not connected to a DSL network.
  • DSL light slowly flashes green: Your modem is searching for a DSL connection.
  • DSL light rapidly flashes green: Your modem has found a DSL network and is connecting.
  • DSL light is red: The modem is unable to connect to a DSL network.  

The next light below the DSL light is that all-important internet light. Here’s what it indicates. 

  • Internet light is steady green: You have active data transmission and all is well. 
  • Internet light is flashing green: Data is being transferred between the server and devices. 
  • Internet light is off: Your modem is in transparent bridge mode. That means it is not broadcasting WiFi. Instead, it is acting as a “bridge” to a separate Wi-Fi router. 
  • Flashing green to red internet light: The Technicolor modem is busy with its configuration setup. The light should settle into a steady color in a few minutes. 
  • Solid orange internet light: Your modem is on, but it is not activated. You will need to call your ISP to activate your service. 
  • Solid red internet light: Network authentication has failed. You will need to check your network settings. 

Moving down to the indicator light that’s fourth from the top, you are now looking at your WAN/LAN indicator. 

  • A solid green WAN/LAN light shows that the WAN/LAN port is connected to your network. 
  • If the WAN/LAN light is flashing green, data is being transmitted. 
  • If it is off, no WAN/LAN port is connected. 

Now for the next light down: it’s your Ethernet LED.

  • A steady green light means that the ethernet port it corresponds to is active and connected.
  • Flashing green ethernet light? Data is being transmitted. 
  • When the ethernet light is off the ethernet port is not being used. 

Now for the light located below the four ethernet indicators. It’s your USB indicator light.

By now, you’re probably able to guess what the different lights you’ll see at this point mean, but here they are anyway:

  • A solid green USB light means that a device is connected via the USB port.
  • A flashing green light means that data transfer is underway. 
  • If it’s off, the USB port is inactive. 

We’re almost done! Let’s check out the wireless LED light on your Technicolor modem next.

  • Solid green light: WiFi is on and working.
  • Flashing green: data is being transferred
  • Orange: WiFi is turned off, but is still enabled. 
  • Off: WiFi is not enabled. 

Now for the last one: the WPS LED. WPS makes it easy for devices to connect to your network. However, it can be a security loophole, so many experts suggest disabling WPS. 

Here’s what the lights mean:

  • Solid green light: WPS is active. After a few minutes, the light turns off by itself. 
  • Flashing orange: WPS verification is underway. 
  • Flashing red: Attempted WPS verification failed. 
  • No WPS light after turning on your modem: WPS is disabled. If you want it on, you will have to activate it using the admin portal. 

Technicolor TC8717T and TC8715D

These Technicolor modems’ lights are similar to the C2100T or C2100Z but less technicolored (white is the only color) and less numerous.

Here’s what you get on a TC8717T:

  • The power button can be white, flashing white, or off. If the light is white, the device is running from mains power. If it’s flashing, it’s running on battery. And off is… well… off. 
  • The next light is the US/DS (upstream/downstream data movement) indicator. If it burns steady white, the US/DS channel is locked (working). If it’s flashing, it’s in the process of locking. And off, as before, means just what it says. 
  • The online light is steady white when connected to your ISP. It flashes when it’s in the process of connecting. And if it’s off, you aren’t connected. 
  • The 2.4 GHz and 5GHz indicators are for your wireless. If they’re on, devices are connected. If they’re flashing, data is being transmitted. And if they’re off, they’re disabled. 
  • Next, there are two phone indicators, also with white lights. Solid lights mean phones are connected and are on the hook. Flashing lights mean the phones are off the hook. If they’re off, there isn’t a phone connected to the port. 
  • Finally, we have a battery indicator light. If the light is steady white, your battery is fine. If it’s flashing, your battery is low. And if it’s off, your battery is dead or there’s no battery at all. 

The TC8715D is even simpler. Below the power button, there’s the US/DS indicator showing upstream and downstream data transfer. 

Below that is the internet light (online) and the two wireless indicators for 2.4 GHz and 5GHz. The lights work in much the same way as they do for the Technicolor modem we’ve just discussed. 

Fixes For Red Technicolor Modem Lights

Just knowing what the Technicolor modem’s lights mean may have already pointed you in the right direction to try some fixes.

But if you are still having trouble with red lights or lights that aren’t on when you want them to be, you can try these DIY fixes.

1. Check That You’ve Activated the Functions You Need and Have Configured Correctly

You can enable or disable functions on your router. For example, your WiFi needs to be enabled for it to work, and if you want to connect via USB, that needs to be activated too.

And, of course, your modem won’t work properly if it hasn’t been set up correctly. 

So, the first thing to do is to go to the admin dashboard using your PC. Let’s say you aren’t able to connect to your ISP. If there’s no service outage, you might need to re-enter your credentials.

You’ll also find the right places to enable or deactivate some of your features. For example, you might want to disable WPS for better network security. 

2. Restart or Power Cycle

Sometimes, simply restarting is enough to iron out red light issues. However, if you still have Technicolor modem lights showing signs of trouble, you might have better success with a power cycle. 

That’s simply a matter of unplugging the power source and leaving everything off for a few minutes so that your modem/router can “forget” the issue that was causing the trouble.

Once it’s been off for a few minutes, plug everything back in and try again. 

3. Try a Factory Reset

Sometimes, a factory reset does the trick when all else fails. However, you will need to reconfigure your system. If you don’t know how to do this, you’ll need help from your ISP. If you do, then go right ahead. 

A factory reset restores your modem to the state it was in when you got it. So, if there are any glitches or configuration issues, they’ll get cleared away and you can start over. 

To reset a Technicolor modem/router, look for the recessed reset button. Press it in and hold it for at least 10 seconds.

Once you’ve done that, it will reset and turn on again with its memory wiped, so you’ll have to go to the admin dashboard and do the setup from scratch. 

4. Check your Cables and Their Connections

You can’t always see damage to a cable, but if it’s kinked out of shape or pinched at a point, your cable can be the source of your modem’s problems. 

Connections are easily checked by plugging out and in and checking whether they fit snuggly. If you can wiggle them, that’s likely to be a sign of trouble. 

Even if things check out OK, it might be worth trying a spare cable (if you have one) since internal damage isn’t always visible from the outside of a cable. 

5. Is Your Modem Broken?

Before checking this possibility out, try calling your ISP. There may be service issues. Sometimes they need to reset your provisioning from their side. And, of course, it could just be a service outage you can’t do anything about. 

If your chat with your ISP’s customer support agents didn’t lead to solutions, the fault may lie with your modem or its cables.

Take them to a store (your ISP’s physical store or a store that sells Technicolor modems) and ask them to test your modem and its cables. 

Most times, your ISP will expect you to pay if a technician comes out only to find that your modem is broken.

You’ll also have to wait for a technician to come around – so this is one way of shortcutting things and it could save you a little money. 

If your modem and its cables seem to be OK, you might have to call for a technician anyway, but at least you’ll have eliminated your modem as a possible cause of the problem. 

Final Words

If you are feeling like a bit of a dummy for not being sure what all your router lights mean, don’t. Most people don’t bother with router lights as long as they have internet.

Most of them will be unsure about why lights are steady, are flashing, have changed color, or are simply off. 

Although different makes and models may use different colors of light, the basic principles are fairly standard across routers/modems.

So, by taking time to understand what those lights are telling you, you’ve probably put yourself in a good position to understand almost any router/modem. 

Knowing what your modem is telling you helps you to identify issues and fix them. That’s good news for you and your family – and maybe even your friends!

Daniele Besana

Daniele Besana

Daniele is a freelancer consultant with 15 years of experience in network security, customer support, Linux and Salsa. He worked for Juniper Networks in Netherlands, providing support and consultancy on security projects across Europe and Middle-East.

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