The generally suggested setups are as follows:
A. Best BUT does not suit many homes.
1. BT Master
2. Filtered Faceplate (eg. ADSL-Nation)
3a). Rear filtered connections = All phone extensions.
3b). Front socket = Short quality rj11 lead (very rare).
4. Router
5. Ethernet (CAT5e) cable to study/office and PC or Switch.
B. Tidy suits more homes.
1. BT Master
2. Filtered Faceplate (eg. ADSL-Nation)
3a). Rear filtered connections = All phone extensions.
3b). Rear unfiltered connection = CAT5e or Twisted Pair Phone Wire
4. Router in study/office.
If you want a more finished installation in would be appropriate to install something like the following at each end and maybe even use a short patch cable from the filtered faceplate:
http://www.kenable.co.uk/product_info.php?products_i... You can also use these if you end up with the router by the master and run true ethernet to the office/PCs. There are double and quad faceplates too.
There are numerous other suppliers including on eBay. Note that prices vary alarmingly and not just because of higher quality parts.
Also note that the router type RJ11 connector fits neatly in the middle of an RJ45 socket. Do label it as ADSL (for Plan B) though as otherwise someone might nuke an ethernet card! If you hunt around you can get RJ11 faceplates/keystones if you prefer.
One thing to watch is that the majority of the faceplate
keystones are designed to work with solid core cable. This is harder to come by in short (< 100m) lengths than long patch leads. Although you can cut the plugs off a patch lead the multi stranded cable used does not suit the rear connectors on most faceplates. Its very easy to be overcharged for cut lengths of Solid CAT5e, even maplin's price is pretty stupid.
Its quite hard to track down quality short router rj11 patch cables. Most are very low quality flat cable, and so not twisted pair. This attracts noise. ADSL nation do sell some although as they are screened BUT most installations won't be wired for this they are sometimes contentious. They are however rj11 and twisted pair!