A good friend of mine pilots commercial airlines and I asked her we're forced to turn off devices, she says it's cause cell phones can interfere in the same way

A good friend of mine pilots commercial airlines and I asked her we're forced to turn off devices, she says it's cause cell phones can interfere in the same way as they do with music equipment. If one rings close to a loud speaker you get that tell-tale electronic ticking sound and she says that can make pilots not understand what air traffic control is saying … Not sure if this is true or if she'd actually experienced it before.