Hi

My digital cordless panasonic phone KX-TG4381AL is making a short constant ringing noise during phone calls. Any ideas what the problem could be? I have checked with modem off so dsl filter doesn't seem to be the problem

Thanks

I am not an expert on this matter but I thought that safety features precluded this from happening due to the possible injury to the ear. I don't believe this phone was designed with circuitry allowing it to ring while in use. Design flaw or faulty phone or improper wirong? Check the safety warnings (which I never read) in front of owner's manual.

Sorry, what I meant was ringing through the phone (as in similar to the noise when waiting for someone to answer, but a shorter and more frequent beeping noise

Just shooting in the dark here.
Have you tried with modem off and filter removed?
Did this hookup work OK previously and problem just started?
Have you tried another phone?
Could a neighbor with same type phone be causing interference?
Does it happen regardless of who you call?
Have you checked with phone company?