I've been fiddling about with my ADSL this weekend. My download sync rate has been steadily dropping from near 8Mb this time last year to just over 3Mb. I'm currently using a Zyxel Prestige 660 modem which allows me to see detailed line data.
Two major changes I've made to get me back to 6.5Mb sync rate were replacing the filters in the lounge (the master socket location) and in the office. At the moment I've got an ADSL Nation XF-1e filter in the lounge and a second NTE-5 in the office that has an ADSL Nation XTE-2005 Master Face Plate on it.
A comparison of the filters can be found at the following page:
I'm still about 1Mb down from what I used to see. To try and rectify this I'm going to firstly try a different modem. I've got a Linksys WAG354G to try first and then I'm going to try running OpenWRT on the Linksys to see how that holds up. I'm hoping that one of the two methods will allow me to graph the line data via SNMP, something that isn't available on the Zyxel.
I'm also going to find out if the second NTE-5 is overkill by replacing it with a filtered faceplate like the ADSL Nation XTF-68 ADSL Telephone Socket or replacing the NTE-5 faceplate on the master socket with the XTE-2005 splitter and running the ADSL and voice over different pairs upto the office and presenting them on a standard double phone socket.
Finally I'm going to get a hardwired ADSL filter to put under the alarm panel. I've got the pair from the alarm panel connected to the voice side of the splitter in the office but I'd like to put as much suppression as possible on that circuit, as close to the alarm panel as possible as it's the only thing connected (apart from the modem) when I run the readings below.