My hand set says line is use though both phones are off. It also says check tel line
Check that the base for the cordless phone system has power. If you have power then the problem may be with your telephone wiring in the house or outside. My standard checks start with checking if the jack is working by plugging in an old wired telephone. If there is a dial tone, then there is a problem with the cordless phone base. If there was no dial tone, then I check for dial tone at another jack for the telephone line with the wired phone. If there is a dial tone, then check the wiring for the first jack. There could be loose wires inside the box. The face plate will have either screw terminals or a keystone jack. You will need to strip the wires and secure them for the first type of jack. To secure the wires for the other type of jack, you do not strip the wires. Instead you will need a punch-down tool available at most hardware stores in the electrical section. Note: if there is a DSL filter inside, you may need to replace that. If you recently had a telephone service upgrade, a wire might not have been connected to the service box. Check behind your siding. (We had one phone extension out of four that wasn't connected after a service upgrade.)
If there is no dial tone, then I check the service box. If you have RJ-11 jacks in the service box, then plug in the test phone and check for a dial tone. If there is no dial tone or you can't test the line, contact your telephone company. They should test and fix outside problems for free. (Some companies may try to get you to upgrade to a non-copper line service instead.) Outside problems can be caused by mice or other animals chewing on the wires or a contractor who cut a cable while digging. Similarly a DSL filter in the service box could be damaged. If you have fiber-optic service, then the problem could be with the modem that translates the signal for the POTS line. If you have isolated the problem to an inside wiring problem that isn't at the jack, your telephone company can send a technician to fix a problem in the wall for a fee.
I hope these ideas help.
(I've contacted my telephone provider about the mice breaking an underground cable a few times. When my household's fiber-optic modem flaked out, we had intermittent loss of dial tone and internet service. Due to the sporadic nature of the outages, it took a while to realize that we needed to call for the unit to be serviced.)
on Feb 29, 2020