Home 250 - Poor Downstream Speed

My mum has a Zen Home 250 service (all she needs really) and it's been fine up until last week. Last Thursday it started playing up; Internet access was painfully slow (took five minutes to load the uk.yahoo.com home page) and she thought it might be her computer or that she'd downloaded a virus or something.

I checked out her PC and it was fine; took it and plugged it into my home LAN and performance was as expected. So I borrowed another router and went back to run some tests to see what might be at fault. Her router is an old Netgear DG814, so not capable of providing any line stats, so I borrowed a new Zyxel P660HW.

I've tried the following:

• Checked the exchange, showing green, and others (friends/neighbours) haven't been experiencing any problems (hence unlikely to be contention);
• Changed all the microfilters;
• Disconnected all the other phones etc.;
• Checked the MTU on the router and PC;
• Tried a different CAT5 lead from the router to the PC;
• Swapped the Netgear for the Zyxel - the Zyxel took ages to sync and was no better when it did achieve a connection;
• Moved everything downstairs and plugged the Zyxel into the test socket in the BT Master - no change.

Using the Zyxel I was able to get some line stats. The connection syncs at 288k up and down (as would be expected for a Home250 connection), whether the router is connected to the test socket or to the normal extension socket that is used. The line stats were as follows:

Extension socket
Noise: 43db down, 28db up
Att: 40db down, 22db up
TB Speedtest: 24.99k down, 241.68k up

Test socket
Noise: 43db down, 31db up
Att: 41db down, 22db up.
TB Speedtest: 26.55k down, 241.68k up

The TB speed test was the only one I could get to work; others (including the BT Speedtester) just timed out.

Clearly there's a problem with the downstream side, but the upstream seems to be fine. There's no obvious noise or quality issue with the voice side of the line. Alas because the Netgear doesn't provide line stats, I don't know if the noise/attenuation figures have changed at all, though I wouldn't have thought that 43db noise margin was particularly bad for a Home250 connection.

It was too late to call Zen TS by the time I'd run through all these tests/checks, so I'm going back over tomorrow evening to give them a call then. Does anyone have any suggestions for other things to check/test before I call them, or thoughts on the cause?

Re: "I wouldn't have thought that 43db noise margin was particularly bad for a Home250 connection. "

Mine is 43db - and runs at the full 256K, so your mother's line should be OK on that score.

A 43db noise margin (if accurate) is excellent. Thats the difference between the signal and the noise remember not the noise.

So it would suggest you have a clean ADSL signal, other testing would suggest the CPE and filters are okay as is the PC and cabling.

Maybe an odd line card issue?

Thanks guys.

I reckon the 43db should be reasonably accurate (most Zyxels I've seen tend to be), and I similarly thought the 43db figure was pretty good.

The line card issue is plausible, looking at the BT Outage Checker there was an issue with our exchange on the 6th (coincidentally the day before her problems started).

We've seen a few cases of problems with Home 250 accounts over the past few days - and are currently investigating this with BT.

I'd advise going through the usual checks, just to be sure it isn't something at your mother's side, and then report the issue to Technical Support.

kind regards,
Phil D.Long

Hi,

Can you PM me your Zen username please? Obviously we're getting plenty of usernames from customers with this problem - but none from those who aren't, so a confirmed working account would be very helpful.

kind regards,
Phil D.Long

Phil,

TS were going to be my next port of call, I'll be going back over to my parent's house this evening in order to phone TS on behalf of my mum and get a call logged.

As far as doing the usual checks, I think (I hope!) I've been pretty thorough and ruled out most things bar the line itself. I know her PC is fine (works on my connection at my house), it's clean of viruses (scanned using two online tools and also replaced her Norton with Kaspersky). I've swapped/replaced the filters, and disconnected things like their Sky box. I've tested with a brand new router (that works fine on another connection so is know to be working) and it gives the same results as her own one, so it pretty much rules out her kit. And I've tested everything from the test socket in the BT Master, so it's not a wiring problem. Everything I've tried points to it being the BT side of things, whether it's the line or the exchange. Oh and I also checked the MTU to make sure it wasn't an issue with that as well.

Did you run a BT speedtest or an ADSLGuide one?

It could be BT or Zen I suppose if the sudden increase in reported faults are unique to Zen?

Probably worth running a BT speedtest if you haven't already.

It was a TB/AG speed test. I couldn't get the BT one to run at all - it kept timing out!

Yes - it's very temperamental but it usually works eventually. Unfortunately the only time you have to test is probably when it's busiest which doesn't help.

It may help to rule out the line though if speeds are normal (if you can get a test done)