There are a few ways to try to work out what type of line you have. The simplest way is to look at your telephone bill and in the line rental section it should tell you the type of lines you are paying for.
If you do not have this information available, you can look at the wiring were the lines are installed. The images below show how your lines will be terminated depending on what type of lines they are.

BT Analogue Socket

BT Analogue Socket
Usually BT installs just a socket but analogue lines can also be installed in distribution boxes and wired directly into the system.


ISDN2 Lines
If you already have ISDN2 you will have one of these boxes.

ISDN30 Box

ISDN30 Lines     
There are a few different boxes that are used for ISDN30. Generally they will look like this one. Telephone Systems can be designed for all of these types of lines and for every different function you require. For help and advice Freephone 0800 021 4433 or ask us a question here