Slow ADSL2+ (even slower than ADSL1)

Hi all,

I've recently upgraded my 8Mbps ADSL connection to ADSL2+. For a while the line was running at 16.6Mbps, files were downloading very quickly (roughly 14+Mbps) and life was good. Over a period of a few weeks the sync speed progressively reduced all the way down to 6.6Mbps. The length of my phone line is approximately 400-500m (the local exchange is just around the corner).

Here's the information from the router - note the downstream margin is 22db

DSL Modulation Mode: ADSL2+
DSL Path Mode: Interleaved
Downstream Rate: 6652 kbps
Upstream Rate: 1001 kbps
Downstream Margin: 22 db
Upstream Margin: 8 db
Downstream Line Attenuation: 20 db
Upstream Line Attenuation: 5 db
Downstream Transmit Power: 12 db
Upstream Transmit Power: 21 db

I've tried a few things so far to try and fix this problem and restore the line back to it's original state. Firstly I replaced the existing RJ11 ADSL wire with a shielded one. Next I moved the router into a different room and connected it directly to the test socket on the BT master socket (removing the front panel isolates all of the internal wiring). I ran the router in this setup for 2 weeks but no improvement seen. I've tested the entire area for noise (using an AM raido set that was very kindly loaned to me from my ISP!) - no significant noise at all, and there are no electrical devices anywhere near the router or phone socket.

If anybody has any further suggestions this would be greatly appreciated. What options do I have to get the line properly checked - do BT offer a service?

Thanks!

I wonder why your target SNR margin has been forced so high. Can you get any error stats from your modem/router, i.e. FEC/CRC/HEC error counts? Which ISP?

I'm using a Linksys WAG200G (ADSL2+ Home Gateway). Not sure if it's possible to see these numbers without accessing more advanced information - if anybody knows how? I'll do some research or ask Linksys support.

ISP is idnet, Simon has been extremely helpful so far in diagnosis although I / He have yet to discover the cause. However I don't believe this has anything to do with the ISP?

Edited by jez_uk1 (Thu 08-Apr-10 17:52:42)

Are you connected via LLU?
If so ask your isp to lower the SNR with a good line you should be able to get around 18- 20 MB as a 3 db Target SNRM on both up/down would be possible, but for stability i would ask them to reset them to the default levels usually 6-DB,

But if there is a line fault,an increase in sync speed will make such a fault more apparent,
If you haven't done so yet Try the BT quiet line test dial 17070 & select option 2 (quiet line test)

Best to use a corded phone and use the secrecy button to prevent any noise being generated from the handset microphone,do this with the BB connected,also try without router connected,But if you can hear noise then you could report it to BT as a PTSN fault,
But do make sure that your equipment is not at fault first,as they will charge a call-out fee (£127.)should the fault lie your side of the master socket basically, if no audible noise can be heard then all you can do is ask the isp to report it to BT ,as only they can report ADSL faults to BT Open-Reach,
But they will i imagine want to do some further testing and make some line con-fig changes to your line before hand, as they too can get charged a fee,

If no fault is found,or the fault is down to your equipment inc internal wiring(extensions) i believe this is around £190 some isp's will pass this on to the customer also,

If you are unable to get the fault fixed(if there is a fault) or get the isp to set up the config better so you get higher sync speeds, then i would ask them to revert you back to ADSL 1 G.DMT 8 MB

Edited by tommy45 (Thu 08-Apr-10 19:51:37)

In reply to a post by jez_uk1:

I'm using a Linksys WAG200G (ADSL2+ Home Gateway). Not sure if it's possible to see these numbers without accessing more advanced information - if anybody knows how? I'll do some research or ask Linksys support.

ISP is idnet, Simon has been extremely helpful so far in diagnosis although I / He have yet to discover the cause. However I don't believe this has anything to do with the ISP?

Try a different router, such as a Netgear DG834GT or a Speedtouch 585.