DSL Troubleshooting Guide
This guide will lead you through the steps in getting your DSL working again
when you are unable to connect to the Internet.
• Power-cycle the DSL modem
Turning the modem off and back on causes it to re-synchronize the DSL signal
and the network connection to your computer. Often, this by itself is enough to fix
a DSL connection problem. To do this, unplug the power cord from the DSL
modem, wait about 30 seconds, then plug it back in. If you are using an external router, power-cycle it as well.
• Check the DSL “Sync” light
“The ‘Sync’ light on the modem (may also be labeled “SYNC/PPPoE” , “DSL”, “WAN” or “Ready”) should be
lit solid, not blinking. This light will flash when the modem is trying to connect to
your DSL service. It should about 30 seconds for your DSL modem to connect
and display a solid light. If the DSL Sync light continues to flash, try the
1. With the exception of your DSL modem, ensure that all devices plugged
into the phone line, including fax machines, satellite receivers, and alarm
systems, have a DSL line filter on them. These filters prevent interference
with your DSL signal. The DSL modem should be the only unfiltered
device on the phone line.
2. If you have PHLO+ or lineshare ADSL, Verify that there is a clean dial-tone on the phone line that is plugged into your DSL modem. You will need a regular analog telephone to do this test.
3. The phone cable coming from your DSL modem should plug directly into
the wall outlet. Try bypassing any splitters or other devices as they can
sometimes cause interference with your DSL signal. We suggest you
remove and re-plug the phone cable into the DSL modem and the wall
jack to ensure the cable is plugged in securely. The cable should ‘click’
when it is pushed into place.
4. Try moving the DSL modem along with its power supply and phone cable
to a different telephone wall jack. There may be internal wiring issues
causing problems with a specific wall jack or group of wall jacks at your
5. Assuming you are using line-sharing DSL (meaning that your phone and
DSL share a line) turn off the DSL modem and listen for audible noise on
the line. If you hear snaps or static when making a phone call, it is likely
that the phone company will need to repair your wiring before DSL will
6. As a final test, running your DSL modem directly into the “MPOE”
(usually a grey telephone box on the outside of your home where the wires
attach from the telephone pole) eliminates the possibility of inside wiring
• Reboot the computer
It seems trivial, but you should always begin troubleshooting computer problems
by rebooting your computer! This is particularly important if your computer has
worked fine in the past and only just began to exhibit problems.
• Are you using a router?
Many people install a router to enable multiple computer to connect to the same DSL line, or to allow wireless network access. If you are not able to connect to the internet, the problem may be in the router and not the DSL line. Try connecting one computer directly to the DSL modem using an Ethernet cable. If your DSL service includes a static IP address, then you will need to change the TCP/IP settings on your computer to connect directly to the DSL modem.
• Verify your TCP/IP settings
If you have recently changed how your home network is setup (for example, by
adding a router) or if your DSL is newly installed, check that the TCP/IP settings
(your IP Address, Subnet Mask, Gateway, and DNS) are correct and match those
provided in your Installation Guide.
• Remove any extra network devices
If possible, remove any network devices (such as hubs, wireless routers, or
network switches) that sit between your computer and the DSL modem. You will
also need to temporarily change the TCP/IP settings on your computer, following
the instructions for “One Computer” setup in your Installation Guide. By running
your computer directly into the DSL modem, you can eliminate the possibility
that the router or other device on your network is causing the problem.
• Check the lights on the modem
Check the status of the various LED lights located on the front panel of the
modem. The “POWER” light should be lit solid. (On some modems, this light is
on the power supply itself.) If the power light is off or flashing, check that the
power supply is plugged securely into the modem, and plugged into a working
• Check the “LAN” light
The LAN light (labeled “LAN” or “ETHERNET”) should be lit solid or blinking
rapidly. The LAN link light will blink when your computer is sending or
receiving data. If the link light is not lit, try the following:
1. Make sure the Ethernet cable connecting your DSL modem with your
computer is plugged securely into the back of the DSL modem. We
suggest you remove and re-plug the cable into the DSL modem and your
computer to ensure the cable is plugged in securely. The cable should
‘click’ when it is pushed into place.
2. If you have not done so already, try bypassing the router and running a
cable from your computer directly into the DSL modem. This will help
you eliminate the possibility that one of these devices may be causing your
3. The cable that connects your DSL modem with your computer may be
bad. Try a different cable if possible.
If you have read through this guide and are still unable to connect to the Internet or have
other questions, call us for help. Our Technical Support staff is available 8:30am-6:30pm
Monday-Friday, and 10am-5pm Saturday at 510-843-6389, or via email at