Understanding and Troubleshooting Connectivity Problems

I would like to take a moment to introduce our customers to the equipment they have and help with some basic troubleshooting that could prove beneficial and get you back online. We currently deploy two ways in which our customers can connect to the internet, Fiber and DSL. Understanding how your connected, can go a long way in troubleshooting connectivity issues. 

First, we will start with Fiber and how it works. We send data through the fiber optic cable in the form of fast-traveling pulses of light. Once it reaches your house it terminates to what we call an “ONT” or “Optical Network Terminal” This is the grey box you typically see on the outside of your house. Its purpose is to receive the signal from us and translate it into an electrical signal your phone or router can use.  These are powered from a source in your house, typically a battery pack mounted in a garage or utility room. The newly generated electrical signal then travels an ethernet cable from the ONT and plugs directly into the router inside the house. Your router than authenticates (typically via a protocol known as PPPoE) and you have internet access.

A diagram of a home with wires and a telephone

Next, is DSL or “Digital Subscriber Line”. DSL works by using traditional phone lines. We generate an electrical signal that travels the same copper cables already in place. This connection also terminates on the side of the house in what we call a “NID” or “Network Interface Device”. This is also typically a grey box however it is not powered at the house, rather from our office. From the NID we create a connection to where you Modem is placed using traditional phone cables and terminate the connection there. Once the modem is plugged into the phone line it can obtain sync with our equipment, authenticate via PPPoE, and provide internet access.

A diagram of a DSL router and a box

Now that we have a basic understanding of how our service makes it into your house, Lets look at some things we can do if we experience issues with our internet service. First, we’ll look at the Router used in fiber applications (U4 is most common,) and the Battery.

Router (U4, typical in Fiber Applications)

A close up of a fiber router with description of each port


  • LED Indicator
  • Solid Green – Normal Operating State
  • Flashing Green – WPS Active
  • Flashing Amber – Booting Up
  • Red – No Service
  • Power Adapter
  • WAN Port
  • LAN Port

We can start our troubleshooting by identifying what the LED on the back of the device is telling us. If it is Solid Green, we need to look at our devices in the home and how they are connected. Check the LAN connection on all hardwired devices (at both the rear of the router and the device in question.) Next, verify the cabling is good between the router and end device (verify there are no cuts/animal chews inline.) For Wi-Fi, verify the device in question is connected to the correct “SSID” (Service Set Identifier) or “Network” and that the signal quality of your connection is not poor. Keep in mind that if the LED is flashing green the WPS functionality of the router is active and looking for new clients trying to connect. Generally, this will only be activated if somebody presses the WPS button located on the back of the router or if it was activated within the router’s software. If the LED is red, this could be for a few reasons. The most common are the connection from the ONT to the router and the battery powering the ONT (more on this later.) Check the cable running from the ONT to the router for damage and verify it is plugged in to the WAN port on the router.

Battery (CyberPower, only used in Fiber Applications)

Diagram of a battery used for fiber installs

The battery plays an important role in connectivity through a fiber optic connection. Its function here is to provide power for the ONT to function. If you are still experiencing issues after troubleshooting the router, verify the power source for the battery pack and the cabling from the battery back to the ONT for damage. If everything looks good, you can proceed to pushing the “Cold Start” button on the battery pack. This should prompt the ONT to power up if everything is connected correctly and there are no hardware faults in question. In its normal operating state, the System status light should be solid green with no other lights on.

Modem (Comtrend VR-3060)

Diagram of a DSL Router


  • LED Indicators
  • Power
  • LAN Ports X4
  • 2.4 G/5G Wi-Fi
  • DSL
  • Internet
  • Power
  • DSL Port
  • LAN Ports x4

Identifying Issues with connectivity while using the Modem pictured above has its advantages. As you can see, there are more LED indicators on the device to help identify problems. The power light should be solid green in its normal operating state. DSL requires “sync” with our equipment to pass data. Check the DSL light and make sure it is solid green. This indicates it is connected as it should be. If the DSL light is flashing, this is the modem trying to obtain that connection. If it does not go to a solid green state, it could indicate a problem with the wiring from the phone jack to the modem. Check the phone line to the DSL port on the back of the modem and verify everything is plugged in properly. Once you establish a solid DSL light check the internet light. This light can be either solid green (indicating internet access) or solid red (indicating no internet access.) If the light is red, this indicates a problem on ESTech’s side, and no more troubleshooting should be required until it is resolved. Assuming everything is good up to this point we can move on to troubleshooting connectivity issues with your devices. The ETH WAN light should not be lit up as that port is not used in a traditional DSL installation. For hardwired devices verify at both the rear of the modem and the device in question. The LED indicators for the ETH ports will flash green when working correctly. Verify the cabling is good between the router and end device and check the wire for cuts or animal chews inline. For Wi-Fi, verify the device in question is connected to the correct “SSID” (Service Set Identifier) or “Network” and that the signal quality of your connection is not poor. This modem has LED’s for both 2.4G and 5G Wi-Fi networks as well and buttons on the front of the unit that toggle these networks on and off. If the LEDs are not flashing green, there is a good chance you can press the corresponding button to turn on the Wi-Fi.

At ESTech we strive to provide the best services to our customers and hope there is something here helpful regarding your internet connection, how it all ties together, and some simple things to help troubleshoot it.

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