"fail: Test ADSL Line Sync" per AT&T Tech Readout

problem here
if you have a copper land line then the adsl is working to be on the internet
that means that there is not a problem with the land line as both telephone and internet work through the same copper line ( different frequencies)
so that indicates that the connection at the wall for the phone is faulty, or if you are using noise suppressors as recommended on the phone line in the house , that unit may have failed and not letting the phone frequency through
which ever way , if the technicians test the line and find it good then you will be up for the cost of a technician to come and check the house phone and connections

a POTs (plain old telephone) line should never be connected to a router. that adsl filter does not make a phone line share a data line.
ADSL is a type of internet service supplied over a phone line. think of it as raw (unusable) when its on the phone line. then you use your dsl filter/splitter to feed the raw internet into a special dsl modem and the other port can be used by a standard phone.

you will know a dsl modem when you see it because its uplink or internet port will only be big enough to fit a phone cord into, not an internet cord. these dsl modems then feed usable internet to your routers and all devices on your network. but, like i said before, at this point it is too late for your phone and internet to share the same wire.

OK, thats not entirely true

pin out of RJ45 internet
1=orange/white *
2=orange *
3=green/white *
4=blue
5=blue/white
6=green *
7=brown/white
8=brown

1,2,3+6 are used in a typical network

if your network is typical you can "get fancy" and use 4,5,7+8 for telephone or even put 2 data lines on the same wire (not recommended for long distances). however, this may involve cutting some wires and splicing them together or something.

http://h10025.www1.hp.com/ewfrf/wc/documentSubCategory?tmp_rule=15720&tmp_task=solveCategory&lc=en&dlc=en&cc=us&lang=en&product=3752459

Please let the fax line be connected to computer itself do not remove , In the DSL line you get a splitter which the lines for phone and ADSL modem connect the splitter to DSL Line and from the Splitter you 2 o/p ports with phone marking or symbol connect the phone line to it and to line port connect the main 8957and then to ADSL line to ADSL modem from the ADSL modem connect to lan port which is behind the computer (not to dial up modem
i.e is fax line ) or the usb port in the computer ...

Good luck...

The DSL light blinking or going out indicates that the DSL modem is loosing sync. This is usually caused by noise on the line. When you get the DSL service you should be given filters to put on all of your phones so that the phones will not interfere with the DSL signal. Those filters need to be attached to anything connected to the phone line that has the DSL on it except for the DSL modem. Other than that the problem could be on the service providers end, something outside your home, or the DSL modem going out. I would suggest that you verify everything is filtered, then contact your service provider so they can run test on your DSL line.

Error 680--- No dial tone
A) Test modem by dialling a number through HyperTerminal or phone dialler. This will test the Modem without using Dialup Networking.
B) Make sure you are using the correct and/or original cable. Some modems used specific wiring which is not compatible with standard modem cables.
C) Check that you phone line is working with a normal phone.
D) Make sure the phone line you are trying to dial on is not a non-standard line, this can cause problems also.
E) If all the above are OK then get a new modem or test in a different location.

so your trying to use a dsl router as just a router -dsl with dialup?

you have the DSL filters plugged into all your telephones, but NOT plugged into the DSL modem?

is the DSL modem configured to automatically connect using your username and password?

have you tried using a different phone cable, or plugging into a different phone jack?

it sounds like you may not have any dial tone. the hiss [white noise] you are hearing is from the dsl modem.try plugging a regular corded phone into the jack to check for dial tone.if there is none,call your phone company.also try plugging the fax machine into another jack where you know there is dial tone.
good luck
wg

that makes three