Router loses sync when the telephone is used

I posted a message a day or so ago regarding my sync speed halving/noise margin doubling. Since then I have discovered using Router Stats that at times the loss of sync and noise spikes appear to be linked to the use of telephones in the house. For example this morning there was no noise on the telephone and dialing did not affect the noise margin. (stable at around 15db). This afternoon noise can be heard when the phone is lifted- each time the phone is used the line loses sync dropping suddenly from 12-15db to zero before resyncing again at 15db. The same problem occurs with different phones in the house in different locations. It is worth noting there have been times during periods of noise on the telephone when the line has suddenly lost sync without the phone being used.

I have been using an ADSL Nation faceplate for years so I am puzzled as to why the phone should suddenly start interferring with the router- could the faceplate have developed a fault or does the noise on the phoneline at certain times of the day indicate a line fault? Also should I contact my ISP or BT over this bearing in mind the problem also seem to affect the phones?

Disconnect your router from the line and plug a phone (via filter) into the test socket within the BT master socket. Do the quiet line test (17070 option 2 on a BT line) at a time you expect problems. If you hear noise contact your phone line provider and report a (voice) fault. Don't mention broadband. Correcting the underlying line fault will often cure ADSL problems.

In reply to a post by davey33:

I posted a message a day or so ago regarding my sync speed halving/noise margin doubling. Since then I have discovered using Router Stats that at times the loss of sync and noise spikes appear to be linked to the use of telephones in the house. For example this morning there was no noise on the telephone and dialing did not affect the noise margin. (stable at around 15db). This afternoon noise can be heard when the phone is lifted- each time the phone is used the line loses sync dropping suddenly from 12-15db to zero before resyncing again at 15db. The same problem occurs with different phones in the house in different locations. It is worth noting there have been times during periods of noise on the telephone when the line has suddenly lost sync without the phone being used.I have been using an ADSL Nation faceplate for years so I am puzzled as to why the phone should suddenly start interferring with the router- could the faceplate have developed a fault or does the noise on the phoneline at certain times of the day indicate a line fault? Also should I contact my ISP or BT over this bearing in mind the problem also seem to affect the phones?

Sounds like you are with BT or a isp that resells the btw product 21cn or ip stream 8mb max , as the DLM will be responsible for the increase in SNR thats what it does when it thinks it See's a fault, and of course this increase of SNR will cause the sync to reduce,
but if you are seeing disconnects when you use the phone even at a 15db margin, then something is definitely wrong, first thing i would do is try with adsl nation faceplate removed (test socket) and see if it still disconnects,(with and without adsl filter and router connected using a corded phone
if it does then do some quite line tests, dial 17070 option 2 , listen if you hear any noises such as crackling ect then you could well have a voice (ptsn) fault, in which case you report it to your telephone service provider if you don't hear any odd noises on the line, then it could be a broadband related fault in which it's the isp who has to raise a fault with openreach

I have tried plugging the phone into the test socket, test socket via adsl filter and test socket via asdsl facerplate. Each time I ran the quiet line test the noise was the same. When I held the phone against my ear there was a definite fuzzy crackling sound in the background. Should I be expecting pure silence from this test or is a certain degree of faint noise expected?

I have also tried monitoring my line stats with my router plugged into an adsl filter at the test socket rather than the adsl faceplate. There were again noise spikes when using the phone although this time the drops were from 14db to 10db. However within a minute of the third phone call ending the margin dropped to -1.5 (!) before resyncing at 15db.

There should be no noise. If you can try a different filter/phone plugged in to the test socket before complaining to whom you pay the (voice) line rental.