Any piece of equipment plugged into your phone jack can act as an antenna and pick up CB or AM/FM broadcasting station frequencies. This is particularly true for cordless phones.
- Disconnect the base unit from the telephone jack.
- Unplug all the charging units (including the base) from their electrical outlets.
- Reconnect the base unit to the jack.
- Plug each component back in one at a time, listening for noise on the phone after each.
- If one phone is causing the problem, unplug that one and try another.
If only one unit is causing the problem, you might want to stop using that unit. Alternately, you can contact the manufacturer for recommendations.