Experiencing Slower Speeds After Migration

[#1]

Hi, I'm new to this forum.   ADLS2+ conversion commenced on 13th March with a total line outage - PlusNet fault ticket raised, which pointed to a BT problem at the exchange.  Eventually connection reappeared on 26th March, apparently on ADLS2+ but with reduced downstream and upstream speeds. 
Speeds before trial:
  Downstream: ~3500 Kb/s (varied through day, sometimes rose to ~4000 Kb/s) 
  Upstream:         459 Kb/s (steady)
Speeds following conversion:
Downstream: 2734 Kb/s (little variation)
Upstream:       380 Kb/s (steady)
From the BT performance tester, IP profile is fixed at 3000Kb/s.  PlusNet advised raising another fault log to get this changed, but the investigation showed "everything OK". 
My router is a Linksys AG241 (V2).   Current info from router status report
  DSL Status:                                 Up     
  DSL Modulation Mode:                  ADSL2+  
  DSL Path Mode:                           INTERLEAVED  
  Downstream Rate:                        4889 Kbps  
  Upstream Rate:                            448 Kbps  
  Downstream Margin:                     6 db  
  Upstream Margin:                         20 db  
  Downstream Line Attenuation:       43  
  Upstream Line Attenuation:           25  
  Downstream Transmit Power:        0  
  Upstream Transmit Power:         0
I'd be grateful for any advice on what to do next to get the line speed back at least to where it was before the trial. 
Moderator's note by David (spraxyt): With the originator's agreement, topic split from Speed Thread since it is developing beyond simple before/after speed comparisons.

[#2]

Can you try plugging the router into the test socket with no phones connected and report the stats. With respect to the upstream rate that needs to be unstuck which will require a new order so won't happen until after Easter

[#3]

Jim,
That took me a while because I had to do some replumbing, taking the router from its normal upstairs location to plug it into the BT test socket (that I didn't know existed!) which is up by the ceiling above our front door.  When the line was installed, BT ran an external cable from this socket to my upstairs study where I normally have the router plugged in - I guess the external cable's about 30' long. 
The stats now read:
DSL Status:  Up   
      DSL Modulation Mode:  ADSL2+  
      DSL Path Mode:  INTERLEAVED  
      Downstream Rate:  6653 Kbps  
      Upstream Rate:  448 Kbps  
      Downstream Margin:  7 db  
      Upstream Margin:  22 db  
      Downstream Line Attenuation:  43  
      Upstream Line Attenuation:  25  
      Downstream Transmit Power:  0  
      Upstream Transmit Power:  0
Hm, I bet you're going to tell me that I should use this ceiling socket now, rather than the upstairs one.  I guess I could do that by installing a shelf for the router above the front door, linking it to a wireless access point relayed to the wired network upstairs ... will take a bit of organising.  (At the moment I've got power cables draped across the hallway to the router and a wireless access point both perched on top of a coatstand within easy reach of the BT test socket - this is OK for a short while, but we can't use the front door!    )
Thanks for your help.  If the upstream rate can be raised after Easter, that will be a big step forward. 
Regards,
Jeremy

[#4]

Or you can try just removing the bell wire from the removeable front plate. These are the wires that go to terminals 3 and 4. The only wires that are needed go to terminals 2 and 5.

[#5]

.... Supplementary info.  With the normal internal phone line plugged back into the BT test socket, and the router then plugged into the external socket on the same box, the stats are now:
DSL Status:  Up   
      DSL Modulation Mode:  ADSL2+  
      DSL Path Mode:  INTERLEAVED  
      Downstream Rate:  5050 Kbps  
      Upstream Rate:  448 Kbps  
      Downstream Margin:  6 db  
      Upstream Margin:  22 db  
      Downstream Line Attenuation:  43  
      Upstream Line Attenuation:  25  
      Downstream Transmit Power:  0  
      Upstream Transmit Power:  0
So it appears the internal phone cabling (a single 10' run to wireless phone controller) may be having more of an impact on ADSL2+ downstream speed than the external BT cable run to the upstairs socket. 

[#6]

Don't fully understand the above but if you have reinserted the removeable faceplate you now have reconnected the bell wire. The bell wire can act as an aerial this will introduce noise on the adsl. See here especially the section on the ring (bell) wire.

[#7]

That's good.  I have now disconnected the bell wire and replaced the faceplate.  Sure enough the downstream rate has improved:
Downstream Rate:  6653 Kbps   
      Upstream Rate:  448 Kbps  
      Downstream Margin:  7 db  
      Upstream Margin:  19 db  
      Downstream Line Attenuation:  43  
      Upstream Line Attenuation:  25
Many thanks for the tip and the useful link.  That's tidied up my line ready for when I (hopefully) get the IP profile increased and the upstream cap removed.

[#8]

Well, this story eventually has a happy ending. 
Downstream connection on my router's status report is c. 6500Kb/s and upstream is c. 850Kb/s.  Even though these numbers are not as impressive as those achieved by some folk, presumably reflecting my distance from the BT exchange, they are  much better than anything I saw pre-ADSL2+. 
Steps to get this far were:
1) I disconnected the redundant bell wire at the BT master socket (see advice received in previous messages) - this greatly improved the signal,
2) PlusNet CSC got BT to raise my IP profile which had got stuck at 3000Kb/s for some reason after the ADSL2+ conversion - the profile now adjusts automatically as it's meant to do.  It's currently at 5500Kb/s.  Actual throughput has settled at around 4700Kb/s downstream with occasional bursts well above 5500Kb/s.
3) Jameseh, in response to a PM, has kindly sorted out the upstream cap with BT and I'm now connecting at about 850Kb/s upstream (with actual throughput of about 750Kb/s)
Thanks to everyone who has given me help and advice on this.  Getting the ADSL2+ service properly configured has taken some persistence over several weeks, but it's been worth the effort.