loud humming on land line cordless phone

Hi @tomehlinger

Is the phone's base station connected directly to a telephone cable or is it connected to a modem and is a VOIP (voice over internet protocol) type service?

If it is a telephone cable connection, it sounds as though there's a line fault e.g. wet cable somewhere, between your premises and the local telephone exchange (telephone switch), which creates noise due to an earth or voltage connection on the line, that shouldn't be there.

Don't know how the fault repair system works where you are but here with this type of problem you can ring the phone service provider (using another phone) and tell them that the line is noisy and that at the moment you have disconnected/unplugged everything from the line at your end so that they can remote test the line to check its condition. If it were OK they would test a clear open circuit line i.e. no foreign earth, no foreign voltage or a leakage to earth condition and no equipment connected to the line

If there is a line fault then they should have to fix it as they are responsible for maintaining the line up to where it enters the premises.

If it tests clear then the problem may be in the wiring within the premises and it is your responsibility to fix it i.e. yourself or pay them or someone else to fix it.

If it is a modem connection, try resetting the modem by powering it off for 5 minutes and then turning it back on again. Allow the modem to initialize before checking the phone service for any noise.