Hi @ndduncan
If you disconnect ''everything'' from your telephone line, what signal do you hear ''in another phone'' e.g. a mobile phone, that you are using to call your landline number, ringtone, engaged tone, voice announcement or nothing at all?
''If you get the engaged signal, voice announcement or nothing'' ''at all'' contact your landline service provider about the problem
''If you hear a ringtone signal,'' use a pair of scissors or a screwdriver to short out the two telephone wires in the phone socket in your premises when you hear the ringtone in the calling phone.
''If the ringtone stops in the calling phone when you do this'', this proves that the line is good to the premises and that there may be a problem with the base station or the cord to the base station, if it is a portable phone or the phone itself if it is a corded phone.
''If the ringtone continues in the calling phone when you do this'' then there is a problem with the line or you're not doing it correctly. If you're sure that you're doing it right then call your landline service provider about the problem.
What is the make and model number of the phone?