Modem with Lights

Troubleshoot and Diagnose Modem Issues

In Customer Information by Fred Arnold

As a customer who utilizes internet equipment, troubleshooting and diagnosing an issue with your modem is often a hassle. These problems stem from many sources such as low signal from the tap, cut lines and roots and other debris eroding the quality of the lines coming into the home. There are back end system errors that may cause low or no signal as well as larger scale problems that might need to be addressed, like requiring a new feed line.

When it comes to technology, a lot can go wrong. As the customer, some issues may not be in your hands to fix, but there are some techniques you can use to verify that your internet is working correctly. They may also solve a problem without getting your ISP involved!

What is a Modem?

First things first! It is always good to have a basic understanding of the technological systems being utilized.

The word modem is actually the combination of two words (modulator and demodulator). Modulation refers to the changing of pitch, tone or other factors into a different frequency. Basically, a modem accepts data, modulates it into a signal that can be transmitted, and then it is demodulated when it arrives to your house via your own modem. Your WIFI works in a similar fashion except it modulates/demodulates radio waves.

Back in the 1960’s everything was done off of terminals that processed data at 300 bits per second. Modems stayed around that range because people were only processing text, but things changed as the web sphere grew more graphical in nature. Graphics (photos/illustrations) and video web components pushed the expansion of transfer speeds into the 300 megabits per second (and beyond) that we see today.

A modem actually converts the information it is receiving into computer language (binary). As you can see with today’s web pages, a large amount of data needs to be processed into something the computer can understand. Modems evolved to push for higher transfer rates, and they progressed in different phases:

  • Frequency Shift Keying – Transmitted information over a telephone line – Slow transfer rate
  • Phase Shift Keying – Similar to FSK
  • ADSL (asymmetric digital subscriber line) – utilized faster data transfer in one direction than another

In the 1960’s terminals were required to access the internet. Nowadays, we connect to an Internet Service Provider (ISP) which connects us to the internet, and the ISP uses Point-to-Point Protocol (PPP) to route information to the appropriate place. Protocols are a bit over the scope of this article, but if you are interested, you can find more information here: PPP, TCP/IP.

Troubleshooting Your Modem

  1. Now that you have a grasp of how information is processed within a modem, it is time to look at ways to troubleshoot potential problems you may run into. One of the best ways to gage your internet problems is to understand the LED lights that are located on the modem. It is a simple thing, but necessary. This is because those lights are meant to be indicators of what the modem is doing. Each modem has a manual that can be downloaded, and it is a good idea to have one on hand. The manual will outline what those lights mean. Another rule of thumb regarding your hardware: always check your power sources! Always ask “Is everything plugged in? “
  2. Pinging a web address through your command prompt can also give you some information pertaining to your issues. This involves pulling up your start menu and typing “cmd” into the search then hit enter. Once you do so, a command prompt window will appear. You can use any web address you’d like, but for an example we will use Facebook. Type ping and hit enter. You should see information starting to populate in the command prompt window. When you ping a website, you are sending packets to that IP address, and the speed of that transform is recorded back to you in milliseconds. Things that you can identify with this approach: Your connection is sluggish which might point to an internal problem within your residence/residential block, or there is no connection at all which could point to a hardware problem or a bigger issue involving your ISP.
    Command Prompt Window Pinging Website

    Command Prompt window – pinging a website.

  3. If you are tech savvy, you can also check into your router management interface to change frequencies. Each router has a different approach to doing so, so utilizing your manual will be your best bet. Many frequencies exist for modems to transfer data over, so choose a frequency that does not overlap to eliminate potential connection issues.

    Image of a router management interface by

  4. Checking your firmware is also another way of diagnosing a possible problem. If your firmware has not been updated in some time that might be the issue. Firmware is the software uploaded into your modem/router that handles different protocols like security and performance, so an outdated firmware package could be corrupted and causing you grief. Check with your modem/router provider for firmware updates, and do not use firmware updates from third party providers as that will constitute a security risk.
  5. WiFi Extenders are also a way to fix possible WiFi issues. If you check your WiFi signal strength (hover over the WiFi signal icon in the bottom right) in one room then the other, and you notice that the other has limited strength, an extender will fix that issue. Also, changing the location of your modem/router may do the trick as well.
    Plug N Play WiFi Extender from Netgear

    Plug n Play WiFi extender that utilizes an outlet for power from

  6. A properly configured PC is also a must for maintaining a solid connection. Is your PC/Laptop devoid of viruses? Have you updated to your most current Operating System update? Are your networks configured correctly?
  7. Check your outside/inside connections. Your inside connections are your outlets. Is everything plugged in? Is the coaxial cable tightened enough to the outlet to allow signal through? On the outside of your house you can check your drop. The drop is the line that starts at a pedestal (where your internet signal is initially coming from), travels to your house either in the air or underground, and attaches to your house at a wall box. The wall box is generally grey in appearance. You can check the drop if it is aerial just by looking up to see where the line is. For an underground drop, you will need to check the wallbox to see where the underground drop is coming from. Damage can occur at any point within your internet system, so checking the infrastructure could indicate whether it is erosion to any lines, disconnected lines, chewed through lines, etc.
    Cable Wallbox

    This is an example of the inside of a wall box from

  8. If you are unable to diagnose and fix the issue after the steps above, it would be best to give your ISP a call. Sometimes the issue may be larger in nature such as an outage that is affecting many people. Outages can occur due to downed lines at different nodes in the system, and can affect hundredths to thousands of customers. If the issue is not an outage, but requires an onsite visit from a trouble call technician, you may set that up with your ISP. They have specialized equipment that allows them to track where in your system a leakage is occurring.

Notes from our Technicians

Our technicians are pretty versed on getting your internet up to snuff. Here are some of the things they had to say about trouble shooting modems.

  • “We have equipment available to us that helps us diagnose a problem with the internet. Things like toners and meters help so don’t panic if you can’t find out what is wrong. Sometimes it does take a more in-depth look.”
  • “The most common types of errors we see is controllers and WiFi not flagged when we pull diagnostic reports. Majority of the time, that can be fixed on the back end and doesn’t involve your infrastructure.”
  • “The easiest ways a customer can trouble shoot WiFi is connecting your laptop or desktop to the hardwire (CAT5) to see if you have internet connectivity at all. Sometimes it is just the router or a configuration issue. You can also pull your IP address to verify service, run a speed test at a website like WhatsMyIpAddress or reboot the modem.”
  • “Always speed test multiple devices, because sometimes it is just the device configuration and not the overall connectivity.”