Identifying Your Phone Line Type
Usually, the easiest way how to tell what type of phone lines you currently have is to check your telephone bill under ‘line rental section’. It should indicate what type of lines you are paying for currently.
How to Identify Types of Phone Line Sockets
If you do not have this information available, the easiest way to find out is to look for an ISDN T/A (modem). If you have a telephone plugged in and it works, follow the wire from the phone to the wall. If there is NO device between the phone and the wall then you have an analogue line.
How do I know if I have Analogue Phone Lines?
If you follow your wire from the phone to the wall, if you see a socket looking like on the picture below, you will know that it is analogue phone line.
How do I know if I have ISDN2 Phone Lines?
The easiest way to check it is by opening your system cabinet and looking for a box resembling the picture below. It will have ISDN2e sign on it.
How do I know if I have ISDN30 Phone Lines?
ISDN30 comes in variety of boxes, the most common BT branded looking similar to the below:
