I have 4-wire jacks thoughout my house, which I have been using for two phone lines - one analog, one digital - from two different companies. A careless (or possibly vicious) technician who came to fix a loss of dial tone connected the analog service to both lines in part of the house so I lost the digital service.
In principle I should be able to disconnect one line and reconnect the digital service, but over many years changes to the phone services have left a jungle of phone wires in my basement - some ancient fossils, some alive - leading to different parts of the house.
How can I check connectivity to find where the incoming lines are connected to particular jacks ?***** Moderator's Note *****
The only connectivity you need to check is the connection to the complaint department at the company that allowed a technician to make the mistake. Get them back out and tell them to fix it.
Bill Horne Moderator