I hope this is of assistance to you.
Max Terminology
One of the most confusing things about Max is not only that the speed varies, but that there are a whole load of technical terms for the different speeds and measurements that are made. The following should help make sense of the different terms you might come across.
Maximum Stable Rate (MSR)
During the first 10 days your connection will be given a value known as the Maximum Stable Rate (MSR). The MSR is the lowest sync speed (line rate) achieved in the first 10 days, not as the name somewhat confusingly suggests, the maximum sync at which the line was stable.
Here's an example. My new Max connection syncs at variable rates between 3 and 4Mbps. It's stable at 3Mbps but occasionally drops the connection at 4Mbps. If conditions change, perhaps I put in a phone extension or change the filters, I now see the modem synching unreliably at 256kbps and dropping every 5 minutes. I then replace all my filtering and the line returns to the previously seen pattern. In this instance my MSR would be 256kbps but I would probably see a stable 3Mbps download rate and synch at 3.5Mbps after the line had stabilised.
The MSR value is solely used to determine when a drop in sync speed would be considered a fault*. It is important to understand it is not a guarantee of speeds that you should expect for your 'up to 8Mb' connection and that Max is rate-adaptive, meaning your speeds will vary throughout the lifetime of your connection. We do not publish your MSR value as part of your Max service...think of it as for administrative purposes only. If you would like to see what data transfer speed you are receiving on your connection please see your BRAS Profile.
*BT will accept a fault report if the line rate drops by 20% or more from your established MSR, this is said to be below the Fault Threshold Rate. e.g. if the MSR during the first 10 days is determined as 5000kbps, a fault can be reported when your sync speed drops to 4000kbps or less.
Sync Speed (Line Rate)
Also known as Line Rate, the synchronisation (sync) speed is the speed at which your ADSL modem or router communicates with the BT Exchange. This is always higher than the speed at which data will actually be downloaded over the connection. The sync rate is determined by your phone line's characteristics, such as line length and quality. The shorter the line and the better the quality the faster the line will sync.
Throughput Speed (Data Rate)
The throughput speed is the maximum speed that data will transfer across the connection. The maximum throughput speed is always lower than the sync speed because the sync speed includes a certain amount of 'overhead data', this is essentially data that makes the connection work rather than the data that gets added on to the web pages and files you download.
I am lucky that I am able to borrow the appropriate equipment to monitor my lines and this sounds to me exactly that which I have on one of my lines ie. Crosstalk which causes intermittent noise you should be able to observe this using a Netgear DG834G Version 3 and Routerstats, ------ that will give almost the same result as the £40,000 quids worth of test gear Ive had on loan. Its sure going to be a big bill for BT when they get our bill for especially their incompetence , lies and threats.
Have a great day.
