Just a quick point. (I'm always repeating myself on this.) If you have a really long line, you should certainly try out a Netgear DG834 _v3_ the earlier model still to be found on ebay for a tenner [!]. This outstanding aggressive router might be the best of the best for you on a very long line depending on the hw used in the exchange, as I've suggested before that there could just possibly be a synergy between exchange and DSL modem where the chipsets come from the same stable. They're so cheap that the experiment is hardly a risk to your pocket.
But my experience is that the Netgear DG834 v4 doesn't hit those same stunning outer-limits speeds compared with the v3. The two have completely different core chipsets. The v4 is recommended for shorter lines though.
I use a Belkin PureAV (~£40) power conditioner / filter / surge protector on the mains into the router and this is fed by a small APC UPS further upstream. This device is as there principally for its mains-borne interference filtering properties. And there's another Belkin Gold surge protector further upstream to protect the UPS, so a surge up the mains would need to take out three devices before getting to the router.
But the most likely threat is a surge down the phone line and there I'm wide open. I don't really have an answer for you on the phone-line side of things and I wish I did.
As it happens you've made me take a look at the green lights on two of my Belkin surge protectors and the green lights have both gone out, which I'm assuming means they have been 'tweaked' by a small surge [?] and so I'll assume that they are no longer working.
So your post has possibly done me a big favour.
