This is not necessarily true. Interference is usually generated within the telephone instrument itself. It cannot be eliminated by the nearby transmitter operator. However, it can be eliminated by filtering and shielding telephone wiring to block out the interfering radio signals from the telephone instrument and its internal components. Telephone interference may result from problems with either the telephone equipment, the lines, or both.
Some telephones are more vulnerable to interference than others.
Telephones with advanced features such as memory functions, or an automatic redial can be more susceptible to interference because the sensitive electronic circuitry that controls these features may act as an unwanted radio receiver. Your local telephone company is responsible for protecting its lines and cables up to the junction box outside of your home or business from radio signals which can enter your telephone and cause interference. Ask your telephone company about the charges before ordering inside wiring repairs. There may be some charges even if you do have an inside wiring maintenance contract. If you lease your telephone instrument from the telephone company, it may provide shielding or filtering to eliminate the interference.