The operational status of your SmartRG DSL modem is indicated by lights (LEDs). SmartRG modems have lights to indicate power, Wide Area Network (WAN), Local Area Network (LAN), wireless (WLAN), Wi-Fi Protected Set-up (WPS), DSL and Internet connection.
Information is communicated by whether the lights are green, red, off or flashing. Activity on a line is often indicated by flickering lights, when the line is active.
Here’s a summary of how to read the lights on SmartRG DSL modems:

The operational status of your TP-Link DSL modem is indicated by lights (LEDs). TP-Link modems have lights to indicate power, the status and activity of the DSL line, and the status and activity of connections to your computer, whether by ethernet or by wireless.
TP-Link modems have lights on the front (8901G and 8950) or the top (8816, 8951, 8961 and 9970).
Information is communicated by whether the lights are on, off or flashing. Activity on a line is often indicated by flickering lights, when the line is active.
This article includes a summary of how to read the lights on TP-Link modems.


Power
Should be solid green. If it is unlit, there is a power problem or the unit is broken. Check that the modem is plugged in and switched on.
ADSL (Asymmetric Digital Subscriber Line)
Flashes green when the modem is synchronizing, will be solid green once synchronization has occurred.
Internet
Will illuminate green when authentication has been successful, and will flash to show data traffic.
WLAN light (Wireless Local Area Network)
Will be solid green or flashing green if a computer is connected to the wireless.
Numbers
These lights correspond to Ethernet ports connected. These will show a solid green light when a computer is connected to the corresponding port by Ethernet cable and will flash to show data traffic.

Power
Should be solid green. If it is unlit, there is a power problem or the unit is broken. Check that the modem is plugged in and switched on.
LAN (Local Area Network)
Should be solid green if a computer is connected to the ethernet port.
ADSL (Asymmetric Digital Subscriber Line)
Flashes green when the modem is synchronizing, will be solid green once synchronization has occurred.
Internet
Will illuminate green when authentication has been successful, and will flash to show data traffic.
The operational status of your Sagemcom DSL modem is indicated by lights (LEDs). Sagemcom modems have lights to indicate power, the status and activity of the DSL line, and the status and activity of wireless connections to your computer.
Information is communicated by whether the lights are on, off or flashing. Activity on a line is often indicated by flickering lights, when the line is active.
Here’s a summary of how to read the lights on Sagemcom modems:

The operational status of your SpeedTouch DSL modem is usually indicated by lights (LEDs). Different modem models vary in detail, of course, but typically they have lights to indicate power, the status and activity of the DSL line, and the status and activity of connections to your computer, whether by ethernet or by wireless.
The Thomson SpeedTouch 585 modems have five lights on the front (Power, Ethernet, WLAN, DSL and Internet) and four lights on the back, which show the status of each of the four ethernet ports.
Information is communicated by the colour of the lights and whether they are steady or flashing. Activity on a line is often indicated by flickering lights, when the line is active.
Here’s a summary of how to read the lights of a Thomson 585 v7 (other models are similar):

LED Light |
LED Status |
Troubleshooting Options |
|---|---|---|
Power light |
steady green |
If it is unlit, there is a power problem or the unit is broken. Check that the modem is plugged in and switched on. |
Power light |
red or amber |
The unit has discovered a problem. Try unplugging the unit from the power and disconnecting it from all cables, waiting more than 5 seconds (for capacitors to discharge) and then connecting it to power again. If the power light goes green, then connect cables. Otherwise, if the power light remains red or amber then the unit is most likely broken and will have to be replaced. |
Ethernet light |
green (steady or flickering) |
As long as there is at least one ethernet cable connected to a working computer. Ethernet traffic is indicated by flickering of the light. To check individual cables, most SpeedTouch modems have green LEDs at the back of the modem where the ethernet cables plug in which will be green (and flicker with activity) if ethernet is active on that particular cable. |
WLAN light |
flashes |
indicate wireless activity. The colour of the light indicates the security mode of the wireless service |
WLAN light |
green |
is highest security, using WPA encryption |
WLAN light |
amber |
is medium security, using WEP; |
WLAN light |
red |
indicates no security (anyone can use your wireless without providing a password) |
WLAN light |
unlit |
wireless is disabled (turned off) |
Broadband (DSL) light |
steady green |
indicating that the unit has detected a DSL signal and is able to synchronize with it. It indicates that the unit is in sync. |
Broadband (DSL) light |
flash green |
During the process of obtaining DSL synchronization, the Broadband light flashes . If it flashes indefinitely, there is a problem. |
Internet light |
steady green |
the Central Office has accepted your modem's login and password and is ready to provide internet service via DSL to your modem. |
Internet light |
red or unlit |
there is a problem |
Lights can indicate only a small amount of information about your modem. To learn more about what your modem is doing, you can view your DSL usage log (this link is also available from the NCF StartPage, under ‘Internet Access’). Often the pattern of connect/disconnects will reveal more information.
It is also possible to log into your modem (there is a computer with a UNIX operating system in there) using a web browser, and then view its event log. For information about the modem’s event log, consult the modem manual for your modem model.
Some older ST585 units have had problems as they seem to reboot themselves over and over. One member solved this by telnetting into the unit via command line and deactivating Universal Plug and Play (UPnP):
$ telnet 192.168.1.254
$ system config upnp = disabled
$ saveall
On Linux operating systems you can access telnet by opening a terminal and typing in “telnet 192.168.1.254” at the prompt.
On Windows XP and Vista operating systems telnet can be accessed by opening “run” and the “cmd” command and entering telnet.
In Windows 7 and 8 you can bring up the command line by entering “cmd” in the search bar.
In any version of Windows you can also run telnet by installing and using the PuTTY free software application.
The internet light is steady green when the NCF authentication server has accepted your modem’s login and password and is ready to provide internet service via DSL to your modem. If the light remains unlit, there is a problem.
If your unit was able to log in earlier and you have not made any changes, an unlit light likely means that there is a temporary network problem (at the Central Office or NCF) making it temporarily impossible to check your login and password. In this case it is best to just wait for the problem to be fixed. You may need to power-cycle or restart your modem for it to notice that service has been restored. If you can get online elsewhere (by dial-up, at a friend’s home or at an office or library), you can check the NCF web site to see if others are experiencing problems. If not, report the problem, although network-wide problems are almost always noticed quickly.
If you are installing your modem for the first time and the DSL light is green but the Internet light is unlit, likely your unit has not been configured with a correct login and password. Check the configuration instructions for information about configuring:
Lights can indicate only a small amount of information about your modem. To learn more about what your modem is doing, you can view your DSL usage log (this link is also available from the NCF StartPage, under ‘Internet Access’). Often the pattern of connect/disconnects will reveal more information.
It is also possible to log into your modem (there is a computer with a Linux operating system in there) using a web browser, and then view its event log. For information about the modem’s event log, consult the modem manual for your modem model.