ADSL Sync Issues

csmager · 15 Apr 2006 at 16:55

Been regraded to Max yesterday, and have been having sync issues. However, I think I know what's causing the resync.

We have a complex arrangement in this house... All cables are underground, and my dad doesn't like cabling outside or overhead.... so:

All lines come in at one end of the house. 1 home phone line & 1 ISDN line go into a BT Versatility PABX system. All extensions are connected to this using CAT5. We also have 1 other line coming in here, which we use for ADSL. The master socket is therefore not in the same place as my router.

As CAT5 goes to all sockets, there're obviously some spare pairs. To the room where the router is, 3 pairs were in use: 1 for voice, 1 for data (pabx system sends out stuff to 'featurephones'), and 1 for a central bell under the stairs. I used the spare as an extension so i could have the router.

Just a few mins ago, the phone rang - and the bell. The router resynced. It might be a coincidence, but i'd suspect not.

So, do I have any options? Or do I just wait for the DLM kit to put a few more dB of SNR on my line?

iamgud · 15 Apr 2006 at 17:55

See what your margin/SNR is on your router. As it is the first day your line is likely synced at a high speed. This will reduce the margin, the lower the margin the more likely the line is to drop, yours is likely under 9. When the bell rings it might be a touching wire or EMP or somethething. :confused:

If it is possible move the router to the master socket.

csmager · 15 Apr 2006 at 18:11

SNR Margin is 6dB, as is set by BT. I would have thought that after 24hrs of crap stability, it might've noticed and wacked it up to 9dB... but it hasn't.

A bell's basically got a relay in it that turns on and off quite fast, which undestanably's going to create a ton of junk on its supply lines, unless it was designed with isolation in mind...

I've just done a couple of tests - I rang the line that causes the bell to ring, and it did lose sync. I also tried it with the bell unplugged, and it still loses sync. So I'm guessing that some equipment that rings (maybe the ring generator in the PABX, which is near the master socket) causes enough interference to chuck it off.

I'll just have to wait for BTs DLM to kick in and up my SNR a bit.

AMDX23800+ · 15 Apr 2006 at 18:38

Some times if your line is too weak for the speed you are currently using then the ADSL will drop when the phone rings because the line can't handle ADSL at THAT speed simultaneously with a phone call. (or that's all i can think of lol)