Occupation:Fiber Tech/PBX Installer/Tier III Support Rep
Location:Nashville, TN
You can try to add an RF choke on the telephone line as close to the base as possible. The best one I can think of easily grabbed is the big, square ferrite clamshell choke that comes with Avaya Partner ACS telephone systems. Any Avaya tech who installs has a few in his box. Loop the line cord through the iron doughnut a couple times and it just may fix it.
This is CABL.com posting #183875. Tiny Link: cabl.co/mVZT