Iowa Code § 34A.4: Requirements of pay telephones and other telecommunications devices to allow 911 calls without depositing coins or other charge.

In a 911 service area, a person shall not install or offer for use within the 911 service area a pay station telephone or other fixed device unless the telephone or device is capable of making a 911 call without prior insertion of a coin or payment of any other charge, and unless the telephone or device displays notice of free 911 service.