The ADSL faceplates we supply for the BT NTE5 line box are made by Pressac who supply BT. These are the exact same faceplate a BT engineer would supply & fit (They are Openreach branded with Openreach instructions). You will notice we have two types-3 way IDC & 6 way IDC. The difference? The 3 way IDC version is a centralised filter-all extension wiring supplied off this faceplate is FILTERED so no need for a seperate filter on each extension box in your house! On the front is an RJ45 port that is unfiltered for connection of ADSL equipment. All well & good if your router/modem is next to your master socket but if it's not then you can't plug it into an extension as the signal is filtered. This is where the 6 way version comes in-the 6 way has two extra IDC pins marked A & B, any extensions connected to these pins are UNFILTERED so you can still have an extension for ADSL equipment. What if you want your router away from the master socket but would also like to plug a phone into that socket? You have two choices:- (1) Use a Microfilter on that extension or (2), use a filtered faceplate such as this one:-

Filtered Line Box

The confusion comes as most people think it's the ADSL device that needs the filter-it isn't-it's any telephone! Centralised filters still make sense as you are only going to need one unfiltered extension for your modem or router.