Section 90.547 - Narrowband Interoperability channel capability requirement(a) Except as noted in this section, mobile and portable transmitters operating on narrowband channels in the 769-775 MHz and 799-805 MHz frequency bands must be capable of operating on all of the designated nationwide narrowband Interoperability channels pursuant to the standards specified in this part. Provided, however, that the licensee need not program such transmitters to make all interoperability channels accessible to the end user.(1) Mobile and portable transmitters that are designed to operate only on the Low Power Channels specified in § 90.531 (b)(3) and (4) are exempt from this Interoperability channel requirement.(2) Mobile and portable transmitters that are designed to operate only in the data mode must be capable of operation on the data Interoperability channels specified in § 90.531(b)(1)(i) ; but need not be capable of voice operation on other Interoperability channels.(3) Mobile and portable transmitters that are designed to operate only in the voice mode do not have to operate on the data Interoperability channels specified in § 90.531(b)(1)(i) .(b) Mobile and portable transmitters designed for data are not required to be voice capable, and vice versa. 67 FR 61005 , Sept. 27, 2002, as amended at 72 FR 48863 , Aug. 24, 2007; 79 FR 71326 , Dec. 2, 2014; 83 FR 30367 , June 28, 2018