"SYNC Timing Synchronization failure", "T3 time-out" and "Re- initializing MAC"
 

Summary - Installed < 1 week. EITHER: SYNC light flashes rapidly OR: READY light flashes slowly. New modem today, connection up for 3 hours after engineer left, then failed again. Argh!!

ntl250 cable modem w/ 10dB attenuator
4 Mb connection, No other services
Ethernet to WinXP

I am supposed to have 4 Megabit broadband. An engineer came on Saturday to install. It worked beautifully all day Saturday.

On Sunday, it stopped. Either the SYNC light flashes rapidly and I get "SYNC Timing Synchronization failure" citing either FEC or QAM, or the SYNC light is steady and the READY light flashed slowly, and I get the two "Ranging" errors quoted in the thread subject. It has been doing that ever since. (*)

Like most other people, I spend ages trying to get through to TS, who treat it like a new problem everytime, and I get frustrated. I had an engineer booked earlier this week, and when I called that morning to confirm, was told there was no such booking on the system. But that is all beside the point...

An engineer came today - young guy from Transcable (subcontractors to NTL). (*) "Murphy's Law" - it started working 1 hour before he came.

I am in a first floor flat, above a shop. He couldn't find the green box outside (or was it gray, I forget). The cables from all three flats go straight down into the ground. So he seemed to think I had less protection or signal filtering or stabilisation or something (tech speak - not sure) than I might have if there was a box outside. He was also surprised at the 10dB attenuator attached to my modem - he hadn't seen one that big before! ;)

He (eventually) got a call back from his colleague, and told him about the frequent re-initializing MAC error. He replaced the modem, registered the new MAC, and received a confirmation text about 5 seconds after the connection seemed to stabilise. Great! All working. Signal strengths at -3/+55.5, whereas the previous modem had reported -3/+61. I left the house to go back to work.

I got home - surprised that the connection was still up. Opened a browser. Joy! Internet! About two minutes later - (caused by the traffic?) - the connection dropped. Back to flashy lights and failures in the CM log.

So I phoned NTL tech support AGAIN. Spoke to a couple of guys in Swansea - very pleasant. No resolution, just another engineer booked - but I got an extension number I can at least TRY and speak with the same guy next time I am forced to phone TS and book yet another engineer. (I digress). They checked the MAC address - seemed ok - did some diagnostics from their end and they said that signal strength was fluctuating.

I have been told it's a modem problem, then a MAC problem, now a signal strength problem. Any best guesses? Or has anyone seen this scenario before?

Next door has cable... and my wireless router ;) (Although not with NTL)
Matthew

Re: "SYNC Timing Synchronization failure", "T3 time-out" and "Re- initializing MAC"
 

Hi and welcome could be return path problem might be faulty port in cab or a loose connector some where along the line

Re: "SYNC Timing Synchronization failure", "T3 time-out" and "Re- initializing MAC"
 

Thanks, Mick. The engineer today did suspect that, but had no way to tell. He had a box reference SAC something or other that he couldn't find, and whoever he spoke to on the phone didn't give him a location for it, just told him to replace the modem - "it's a MAC address problem..."

Noted - I'll try and make them look harder next time...

PS. I am on NTL just now - -1.9/+61 (snr~39.4) - how long will it last...

Re: "SYNC Timing Synchronization failure", "T3 time-out" and "Re- initializing MAC"
 

Hi Iam in Guildford with similar problems ie disconnections see post "intermittent 4 Meg connections".I find NTL Tech support leaves me speachless.

Re: "SYNC Timing Synchronization failure", "T3 time-out" and "Re- initializing MAC"
 

Speechless indeed - on hold for the most part! I hope that the next engineer is able to do more than give me a new modem...

What's your postcode? PM me if you prefer...

Does anyone know if downgrading from 4Mb to 2Mb is likely to increase reliability? I don't know how cable works - are there multiple carriers on the same line?

Re: "SYNC Timing Synchronization failure", "T3 time-out" and "Re- initializing MAC"
 

My connection has been up since Saturday, although an engineer is booked to come out this morning. Touch wood, it will not go down again...

Intermittent failures are the worst!

How has yours been Chris? We ARE in the same postcode area.
Matthew

Re: "SYNC Timing Synchronization failure", "T3 time-out" and "Re- initializing MAC"
 

Engineer has just left - said it was a probably an upgrade in progress, with poor internal communications resulting in customers not being informed. He has been up and down the street this morning - same symptoms, (same problem...), and all seem to have resolved themselves on Saturday - a reassuring visit.

A victim of bad timing,
Matthew

Re: "SYNC Timing Synchronization failure", "T3 time-out" and "Re- initializing MAC"
 

Hi MicroMatt
good to here there has been some progress. Its all to much of a coincidence but my connection seems to have setled down and my upstream level has gone from a fluctuating 50 to 61dbmv to a steady 40 dbmv at the moment.Also the unicast maint ranging has stopped giving error messages in the modem log. From the NTL service page there is work going on in the Guildford area. Lets hope it stays working,at least I got a new modem out of it.
http://www.ntl-isp.ntl.com/ServiceStatus/

chrisntl