I've had the unlimited service for nearly 4 years and have had very few problems. My connection speed has always been in excess of 7Mb which considering I'm about 3.3 Km from the exchange is good. In January "My Sky" indicated that line testing was taking place and subsequently my speed increased to 9.3MB with a downstream SNR of 6.3dB this remained rock steady until just over a week ago when it dropped to 4Mb but with an SNR of 14.1 dB. A sky line test revealed no problems and post test it reconnected at 9.3MB again but only for a couple of hours or so. Since then it's dropped regularly and speed is around 5-6 MB and the SNR has been between 5 and 14 dB monitoring with Routerstas Lite. I've done all of the internal checks, changed routers (SR101 to F@ST 2504n and back), cables, and filters all with the router(s) connected to the test socket. Openreach came on Friday and found no issues, they replaced the face plate with the new version and their kit showed an SNR of 7dB at the time they were here (but as it varies I don't believe this was indicative of the line) yet it would only connect at 6.3MB - Sky had earlier set a profile of 8MB. Connections were checked at the cabinet and DP but with no improvement.
The upshot is that OR say the line is fine "and meets the parameters for voice telephony'", Sky says it isn't and is trying to pass it back to OR for an extended monitor. Not being sure of the demarcation of ownership of exchange equipment my question is could this be exchange (cross connect/linecard?) related and if so whose responsibility is it to check/test/fault find, Sky or OR?
(The 170707 test reveals no echo or noise and the line is quiet in any case.)