DSL Status Light Blinking

Problem: The DSL's Modem light is blinking, does not turn steady-green, does not connect properly.

This is an excerpt from a longer Keyliner article: 
Installing Netgear DM111PSP ADSL2 Modem

Netgear DSL modems look like this; other brand modems will behave similarly.

Power (top icon) = Green
Ethernet (second icon) =Solid or blinking green
DSL Light (third icon) = Green

If the DSL's DSL LED is blinking and does not authenticate, consider the following


Likely solution:

The DSL Light 
If Off - No DSL signal
If Solid Green - DSL signal detected, all is well (normal state)

If Blinking Green - (blinks on power-on initialization); afterwards, indicates unable to authenticate.  If it continues blinking consider these points:

• Confirm the DSL login credentials, typed in the DSL's configuration screen, are correct.  You will find this in your first-time setup papers for the DSL circuit.  This is not a user-id/password that you type very often.  If you do not have this, call your ISP.
   
• Confirm the data-line to the DSL modem does not have a filter installed.  If the filters check out okay, disconnect all land-line phone devices in the house, including other phones, caller-ID boxes, answering machines, TIVO or Satellite boxes, home security systems.  Confirm there was not a DSL filter installed at the phone company's demarcation point into the house.  Reboot the router and test again.  If the LED goes solid green, you are probably missing a DSL line filter on one of those devices.
   
• If you have multiple phone lines, confirm you connected to the correct circuit.  Although rare, it may be necessary to swap DSL signals on pins 1 and 4 on the RJ-11 jack.  Contact your ISP for instructions.  Be aware this DSL modem uses pins 2 and 3 for its signal.
   
•  Confirm with your ISP that you have an ADSL circuit (this netgear modem is an ADSL2 modem).  Some jurisdictions are running a newer type of DSL line called VDSL.  Contact your ISP to determine.  If you have a VDSL circuit, this modem will not work and it will not be able to authenticate.

If this does not resolve the problem, contact your ISP and ask them to test the line.  This may also indicate a poor-quality or damaged line in your house.


Related article:
Installing Netgear DM111PSP ADSL2 Modem