How to identify your master socket (and install an I-Plate)

This guide will help you identify if your master socket is compatible with a BT Wholesale I-Plate or BT Broadband Accelerator. If you already know what kind of socket you have, check our telephone socket identification guide page to see if it is compatible. A newer version (MK4) which is a VDSL Interstitial faceplate, which is curved and Openreach branded is also now installed by Openreach, will not fit old-style master sockets with screw fronts.

What is an I-Plate

The I-Plate (Interstitial Plate) is a device developed by Openreach which fits on to your master telephone socket which can help improve the performance and reliability of your broadband service if you have telephone extensions connected (even if you have no phones plugged in to them). 

The I-Plate has largely been replaced by service specific faceplates (SSFP) which provide an additional filtered socket for ADSL/VDSL and services. If having a line installed or a master socket replaced by Openreach ask about having one fitted, alternatively some providers have their own 'boost' engineers who will be able to fit them but they fit the same was as the I-Plate so most people can fit them anyway.

The master socket is usually the first socket where the telephone line comes in to the property and is where the I-Plate needs to be installed. If you are unsure what type of master socket you have, please look through our guide below to help identify your socket and see if yours is compatible.

Instruction Video

Step 1: Measure the width of your socket

BT Master Socket Size Comparison

If your socket is around 68mm wide it is an old style socket or an extension socket and you cannot use faceplate filters or the BT I-Plate on this socket.

If your socket is around 85mm wide it is a newer style socket and may be compatible. Proceed to the next step.


Step 2: Identify if your faceplate is a 'split' type (NTE5)

BT NTE5 and non-split faceplates

A 'split' type master socket, known as an NTE5, has a horizontal groove in the phone socket and the screws and socket are located in the lower half of the socket. A non-split socket will have the sockets and screws in the middle. You can also identify a split socket looking at the side as bottom half comes out separately.

BT NTE5 and non-split faceplates side view

If you have a split type socket, proceed to the next step.


Step 3: Check what kind of faceplate

BT NTE5 Master Socket Exploded

A Standard rectangular faceplate is shown (left) removed from the master socket (centre) and back-box (right). You should not remove the master socket from the back-box as this is BT property and should be opened by engineers only.

ADSL faceplate filters

If you have a faceplate which sticks out, then it's likely to be an ADSL filter faceplate. These allow you to filter all your telephone extensions in the master socket, which means you don't need individual micro-filters on each phone extension socket. If you have one of these then you would not benefit from a BT Wholesale iPlate.


Step 4: Identify the type of master socket

NTE5 Master Sockets

A newer socket which has an "Openreach" logo on already has the function of an I-Plate built in so you wouldn't benefit from installing one in this case. Any other split sockets (such as those with the "T" logo or BT "Piper" logo) should be compatible and an I-Plate may help improve your broadband speed or reliability.

BT T Logo BT Piper Logo BT Openreach Logo

 A new curvy style of Openreach master socket exists the NTE5C, this is often called a tool-less master socket, since the engineers who fit them only need a screwdriver to attach the master socket to the wall box. All the extension wiring is done without the need for tools.

NTE5c Master Socket

The width at 85mm is identical to previous Openreach master sockets and the removeable faceplate detaches by pressing on the two bumps on the side, which once removed disables the extension wiring even though this is attached to the wall mounted component. Older style faceplates and faceplate filters will not fit the curved design you need a NTE5C specific faceplate.

Step 5: Buy an I-Plate

The I-Plate is available from various online retailers such as Amazon for around £15. The version available may be an updated version from that pictured. The majority of faceplates include a DSL specific socket for ADSL, VDSL2 or and the phone socket is then also filtered so you do not need to use microfilters at extension sockets.

Step 6: Fit an I-Plate

NTE5 and I-Plate

The I-Plate fits between the standard faceplate and the BT master socket as shown. See our video guide to see how to fit an I-Plate.

BT Wholesale I-Plate