With the DSL light always flashing, it means that either the ADSL signal (synchronization) does not reach your modem, or your modem cannot 'read' the signal.
You need to determine if the problem is from one of the following places :
- outside of your house (your land line or ISP equipment) or from the modem;
- your telephone-cable inside your house or
- one of your equipment;
Try the following manipulations to determine from where the default comes :
- Determine if the problem is in your house or on the land line
- Unplug each and every equipment which is connected to your telephonic installation (Fax, phones, answering machines etc);
- Using the shortest telephone cable (RJ11) you possess, plug only your modem to the main telephone jack of your house.
- If the DSL LED still flashes continuously, the problem is somewhere between your ISP's equipment and your house. You should call them and expose the situation. At this stage, you can't do much else.
- Determine if the problem is in your house installation
If the DSL LED lights up when it is plugged to the main telephone jack, then it is either one of your equipment which is at fault, or the house installation. To pinpoint the problem, do the following :
- With all the other equipment still unplugged, try the modem on all the other telephone jacks you have around the house.
- If the DSL flashes continuously on one of the jacks, you will have found the source of your miseries. Depending on your ISP's terms and conditions, you will either have to call them of call for the services of a third-party technician to solve the problem.
- If the DSL lights up correctly on all the telephone jacks, then your house telephone installation is good. Proceed to the next series of tests.
- Determine which equipment is at fault
- Plus your modem to one telephone jack and wait for the DSL line to light solid.
- Use a splitter (ADSL filter) to plug the equipments you possess (telephone, fax etc) one by one. Verify each time if the DSL LED is still lit or flashes continuously.
- If one of the equipment causes the DSL LED to flash, it is that equipment which causes your problem.
- If every equipment causes the DSL LED to flash, the it is the splitter (ADSL filter) which is causing the problem. You can confirm this hypothesis by testing each and every ADSL filter you have in your possession.
- Replace any faulty equipment and you should have eliminated the problem.
If nothing of this solves your problem, you won't have any choice but call you ISP. Don't hesitate to tell them all tests you will have done.May I also make some recommendations :
- Use a power surge protector (not a UPS though) to plug your modem to the electric outlet BUT plug it directly to the telephone jack;
- Make sure your modem is plugged in as far as possible from UPS, television, etc.;
- If possible, don't plug the modem in the same electric outlet as other equipments;
- Don't use any telephone extension cable to plug your modem to the telephone jack.
Hope this helps you. Let me know what happens next.