Public entertainment forums must alter the radio frequency used for their wireless microphones under an order issued Friday by the Federal Communications Commission.
The groups have until June 12 to find other radio frequencies, something the theaters said could cost thousands of dollars per institution but that they can do.
The FCC's ruling relates to a broader shift in the way the nation allocates precious spectrum used to transmit signals for mobile phones, TVs, and other devices. The commission said the transition was necessary to make spectrum in the 700MHz band available for use by next-generation wireless services for consumers and public safety agencies.
Use of much of that spectrum has been licensed for around $20 billion by major wireless carriers.