AT&T Midwest → DSL Modem Keeps Losing Sync *RESOLVED*

Have been DSL customer since Jan 25. Started out with 3MB/512KB plan and 1 week later upgraded to 6MB/768KB.

Ever since the upgrade, my DSL Motorola modem keeps losing sync and the only way to recover is to power cycle it. I normally have it in front of my Linksys WRT54G router, but have most recently connected my PC directly to it to eliminate the router as a cause. Either directly connected from PC or router I experience the same thing.

Observations
1) The modem is hot to touch. Nothing on top/below it - good airflow all around.
2) Internet LED not lit when this happens, but no red DSL LED either until after I try to hit some websites, then DSL LED goes red.
3) Looking through the log file after it comes back from a power cycle(I have "Keep Log on Restart" enabled for the time being), I see the following entry:
2008/02/04 18:01:29 GMT | L4 | lcp: link dead - closing connection
2008/02/04 18:01:35 GMT | L3 | PPPOE: Sending PADT packet for PPP , Session 0x19b3 is closed

Those are always the last entries in the log before I see where it croaks when I pull the plug.

4) I have only 1 phone connected to my house jack - and it has filter on it. Modem connected to the 2-wire (duplex) filter on a jack of it's own.

This happens several times a day and is very frustrating. I left cable due to ISP issues, but so far my DSL connection has been down more than my cable modem ever was. I have to believe something is wrong with the modem - as I'm running with the same router I had on the cable modem - but problem occurs wile on and off of router.

Any insight or help would be extremely appreciated.

Edit => forgot to add Technician Readout... (MAC/IP addresses have been filtered out)

 
140  Current Rate  6016 768
141  Previous Rate  0 0
142  DSL Max Rate  - -
143  DSL Min Rate  - -
144  Current ATTN DR  7712 1056
145  Current SNRM  9.0 18.0
146  Current LATN  33.0 16.0
147  Current SATN  - -
148  Current TP  15.2 11.0
 
 
 

Edit 2/6/08 -> removed all but "important lines" from code

The only parts of the tech readout worth posting are:
140 Current Rate 6016 768
144 Current ATTN DR 7712 1056
145 Current SNRM 9.0 18.0
146 Current LATN 33.0 16.0
148 Current TP 15.2 11.0

The download side s/n ratio of 9 dB is troublesome but not a killer. However you will have to make sure you don't have any disturbers on or near your phone line. My 6016/768 line at home runs about what yours does and once I ran down all of the marginal connections both inside and outside it's been pretty stable. The authentication (PPPoE) part of the equation has been an issue though.

Yours seems to be an equipment problem especially if the modem is running that hot. I have not seen the Motorolas but so far what I have read about them is not good. Can you borrow a different modem from someone?

Sorry for the long code. Unfortunately no one I know has DSL. Is there a warranty on these modems? Should I go ahead and call AT&T and ask for a new modem - it's only 2 weeks old?

I just installed the AT&T Self Support Tool in hopes of that being able to catch something or shed some more light on the problem, although it doesn't appear to be a very robust application.

There is supposed to be a one year warranty. I'm not sure who handles it though.

The AT&T Self Support Tool is barely more aware than your average paving brick. I'm not sure it will tell you anything useful.

Your modem logs are not showing sync loss though. It's losing the PPPoE session. While that can be caused by sync loss the modem should be showing that too, and the snippet you posted does not have any DSL ("DMT") entries.

AT&T has a modem warranty for modems they issue.
AT&T Yahoo HSI Equipment Warranty Info

The one log message that comes close to a dsl entry is "L4 RFC1483-1 up"

If it keeps losing sync, perhaps your line quality isn't able to keep those speeds. You have to have a fairly clean line to support higher speeds, if your lines aren't up to par, high noise could greatly degrade your speeds or even reduce the ability for the modem to stay synced.

Huh?

Although it may be too early to celebrate, I think I figured out my problem. After reviewing the online version of the installation guide, it states that if the modem is connected to a jack by itself then a filter is not required.

Well, I had a dual stand-alone filter connected to the wall jack and the modem so I removed it. This has been the longest I've gone without an interruption or needing to power cycle the modem since last Monday when the upgrade was complete. If I can go overnight without any problem I'd say case solved.

Thanks to those of who who have responded. I'll update you when I know more.

Well, it's been almost 13 hours since my last post and have not had any sync problems. I was just able to remote my PC from work so my line is up and active. I'm having a hard time believing that the dual stand-alone filter mentioned above that I was using was causing all my problems, but that appears to be what has happened.

Running clean w/o the filter.

Those filters can be trouble. If the modem is on the jack by itself you certainly don't need it (as you discovered). Good luck!

hi - any other link to show what a dula stand-alone filter looks like...

Not sure what or how the filter would impact the DSL modem ?
Since it's passive, what could be the impact - inserting too much attenuation - but those numbers looked ok ?

Does this look like the Dual Stand-Alone Filter?

It could cause the problem if you had the modem plugged in the phone socket and not the DSL socket. The DSL is connected directly to the input on the filter and the phone is through a low pass filter.

Yes, that is the stand-alone filter... one jack for phone, the other for the modem. Mine, that came from AT&T, actually say "2Wire DSL Filter for single-line phones", but has 2 jacks, one for phone and the other for DSL modem.