differance in speed

Could any one explain to me the differance in speed i get fom Demon ( been with them for years ) averaging 2.7 meg download, costing £24.46 a month. Now I have two phone lines to my house from the same exchange, Ryde on the Isle of wight, it enters the building in one cable to two telephone sockets.
B T offered me a 18 month contract at £9.99 a month, ( thought that would save me £270.00 over 18 monthes ) so i accepted the offer but had it put on the other phone line so I could carry on using Demon till all set up and running, so pleased i did.
I can only get 0.7 max down load speed after several weeks, B T help line said I couldn't get my stated speed from Demon as the lines woud only support 2.0 meg max speed. What I would like to know if any one can help me why the differance,
Is B T cutting speed due to low cost, Looks like I will have to write off the cost of using B T so glad didnt go for a higher rated package. Sorry not a techy guy just would like to know same exchange same distance same cable why the differance.
in speed

Just to add, B T sent me a box to put on my existing one and said that should improve the speed it had no effect at all still 0.7 meg. put it on my other line and can now get 3.0 meg sometimes on Demon

Please post your modem stats:

http://www.kitz.co.uk/adsl/frogstats.php

Those give us a good idea of the quality of your telephone line. Different lines can take different routes even if they service the same building.

Edited by Andrue (Sat 05-Sep-09 15:41:45)

run speedtester.bt.com on both lines and post the results.

It's the two pairs in a single cable.

Would they go back to the exchange via the same route, or might they split out at the cabinet so possibly follow different routes as you say?

(Genuine question not a quibble).

the cabinet may be fed by more than one E side cable hence the cable spec / routing could be different for two lines in the same property - esp if there was a big gap between the two being installed.

Sorry, I treid to explain clearly but failed.

It is a single cable from the premises to the cabinet, or a pole, or similar junction. What I'm getting at is whether the cable is routed back to the exchange from that/those, or the individual pairs.

the D-side cable goes from a cabinet (or similar PCP) to the premises. It is terminated in the cabinet and connected to an E-side cable to the exchange. There may be more than one E-side hence the commonality of the line may cease at the cabinet.

That is probably meant to answer it, but doesn't do so clearly.

What you are saying it seems is:-

First that both pairs get to the cabinet quite independently of what might happen for example at a telegraph pole. I was thinking about this while walking the dog and concluded that the the unused pair probably wasn't connected to anything at the pole. However on further consideration that would be silly as it would mean a trip up the pole in exactly the circumstances of the poster - to add a second line.

Second you seem to be saying that although both pairs have been connected to the same on-going cable at the pole, only one pair is connected at the cabinet for connection to the exchange. Which is the nub of my original question. If both were initially connected then surely they would either, as a general principle, both be always to the same E-side cable or always split between two E-sides for future resilience. The latter being unlikely.

The feed into a typical house hold may contain 2 pairs. If the feed is overhead it will likely terminate on a pole where the distributon point is. It is not common practice to pre-connect both pairs at the DP (whether overhead,underground,external,internal)as the D-side will likely be used for another premises at some point.. If multiple pairs were pre-connected then a lot more D-side cables would be required and largley un-used.
The D-side cable will end up at the cab and terminate there. As and when pairs are required they will be connected to available E side pairs. There is often more than one E side cable which may take a different duct route and may be of different specificatiion .

In reply to a post by RobertoS:

It's the two pairs in a single cable.

Would they go back to the exchange via the same route, or might they split out at the cabinet so possibly follow different routes as you say?

(Genuine question not a quibble).

A fair question and I don't really know the answer

We have three lines at our office. They are all in the same bundle and we assume they take the same route through the village then to the exchange in town. All are 54db. One holds steady at just over 3Mb. Another holds steady at 2Mb. The third is up and down more often often than a [censored]'s knickers and rarely gets above 1.5Mb even on a good day.

Maybe it's routing, maybe it's something else.

Edited by Andrue (Sat 05-Sep-09 20:43:10)

In reply to a post by rogan8:

The feed into a typical house hold may contain 2 pairs.

Not mine

When I had Home Highway installed the engineer ran into a bit of a problem. All the lines around here are underground and when he undid the cover on the riser three or four cables sprang out. At that point he commented "Oh, now I remember - didn't this used to be the office of a taxi company?".

I've know idea if it was or not (seems a bit odd, tbh) but unfortunately he'd already unplugged the old master socket inside the house. It took him many minutes to work out which pair was the live one . Maybe he learnt a lesson there

Thanks rogan, exactly what I wanted to know .

Which answers the original point that was made that two lines to the same house can take different routes, which in a way we knew, but wasn't clear to me in the case of a single cable to the house.

Rogan answers the question for us though.

Hi Phil,
Here are results.

bt line.
download speed 678kbps. max achivable speed 1000 kbps
dsl connection rate 992kbps (downstreem) 448 kbps (upstreem)

Demon line.
download speed 2579kbps max achievable 7150 kbps
dsl connection rate 4512 (downstreem0 448kbps (upstreem)

Used the same lap top for both tests.
Cable to the house is a single line goes to pole then down underground exchange about a mile away.
Like to thank you and all who posted thanks for the input, looks many reasons for slower speed on bt line was allocated to this house over 20 years ago, had the extra line (demon ) installed 8 years ago and inbetween ryde exchange was extended, so its probably on newer equipment.
will reply to others on specific points.
Many thanks John

These results are a bit thin for anyone to comment!

You need at least in addition:
Modem Stats: Attenuation & Noise Margin
BT Speedtest: IP Profile

Full results preferred.