Sec.  2.1043   Changes in certificated equipment.

   (a) Except as provided in paragraph (b)(3) of this section, changes to the
   basic frequency determining and stabilizing circuitry (including clock or
   data rates), frequency multiplication stages, basic modulator circuit or
   maximum power or field strength ratings shall not be performed without
   application for and authorization of a new grant of certification.
   Variations in electrical or mechanical construction, other than these
   indicated items, are permitted provided the variations either do not affect
   the characteristics required to be reported to the Commission or the
   variations are made in compliance with the other provisions of this section.
   Changes to the software installed in a transmitter that do not affect the
   radio frequency emissions do not require a filing with the Commission and
   may be made by parties other than the holder of the grant of certification.

   (b) Three classes of permissive changes may be made in certificated
   equipment without requiring a new application for and grant of
   certification. None of the classes of changes shall result in a change in
   identification.

   (1) A Class I permissive change includes those modifications in the
   equipment which do not degrade the characteristics reported by the
   manufacturer and accepted by the Commission when certification is granted.
   No filing with the Commission is required for a Class I permissive change.

   (2) A Class II permissive change includes those modifications which degrade
   the performance characteristics as reported to the Commission at the time of
   the initial certification. Such degraded performance must still meet the
   minimum requirements of the applicable rules. When a Class II permissive
   change is made by the grantee, the grantee shall supply the Commission with
   complete information and the results of tests of the characteristics
   affected by such change. The modified equipment shall not be marketed under
   the existing grant of certification prior to acknowledgement by the
   Commission that the change is acceptable.

   (3) A Class III permissive change includes modifications to the software of
   a software defined radio transmitter that change the frequency range,
   modulation type or maximum output power (either radiated or conducted)
   outside the parameters previously approved, or that change the circumstances
   under which the transmitter operates in accordance with Commission rules.
   When a Class III permissive change is made, the grantee shall supply the
   Commission with a description of the changes and test results showing that
   the equipment complies with the applicable rules with the new software
   loaded, including compliance with the applicable RF exposure requirements.
   The modified software shall not be loaded into the equipment, and the
   equipment shall not be marketed with the modified software under the
   existing grant of certification, prior to acknowledgement by the Commission
   that the change is acceptable. Class III changes are permitted only for
   equipment in which no Class II changes have been made from the originally
   approved device.

   Note to paragraph (b)(3): Any software change that degrades spurious and
   out-of-band emissions previously reported to the Commission at the time of
   initial certification would be considered a change in frequency or
   modulation and would require a Class III permissive change or new equipment
   authorization application.

   (4) Class I and Class II permissive changes may only be made by the holder
   of the grant of certification, except as specified below.

   (c) A grantee desiring to make a change other than a permissive change shall
   file an application on FCC Form 731 accompanied by the required fees. The
   grantee shall attach a description of the change(s) to be made and a
   statement indicating whether the change(s) will be made in all units
   (including previous production) or will be made only in those units produced
   after the change is authorized.

   (d) A modification which results in a change in the identification of a
   device with or without change in circuitry requires a new application for,
   and grant of certification. If the changes affect the characteristics
   required to be reported, a complete application shall be filed. If the
   characteristics required to be reported are not changed the abbreviated
   procedure of  Sec. 2.933 may be used.

   (e) Equipment that has been certificated or formerly type accepted for use
   in the Amateur Radio Service pursuant to the requirements of part 97 of this
   chapter may be modified without regard to the conditions specified in
   paragraph (b) of this section, provided the following conditions are met:

   (1) Any person performing such modifications on equipment used under part 97
   of this chapter must possess a valid amateur radio operator license of the
   class required for the use of the equipment being modified.

   (2) Modifications made pursuant to this paragraph are limited to equipment
   used at licensed amateur radio stations.

   (3) Modifications specified or performed by equipment manufacturers or
   suppliers must be in accordance with the requirements set forth in paragraph
   (b) of this section.

   (4) Modifications specified or performed by licensees in the Amateur Radio
   Service on equipment other than that at specific licensed amateur radio
   stations must be in accordance with the requirements set forth in paragraph
   (b) of this section.

   (5) The station licensee shall be responsible for ensuring that modified
   equipment used at his station will comply with the applicable technical
   standards in part 97 of this chapter.

   (f) For equipment other than that operating under parts 15 or 18, when a
   Class II permissive change is made by other than the grantee of
   certification, the information and data specified in paragraph (b)(2) of
   this section shall be supplied by the person making the change. The modified
   equipment shall not be operated under an authorization of the Commission
   prior to acknowledgement by the Commission that the change is acceptable.

   (g) The interconnection of a certificated or formerly type accepted AM
   broadcast stereophonic exciter-generator with a certificated or formerly
   type accepted AM broadcast transmitter in accordance with the manufacturer's
   instructions and upon completion of measurements showing that the modified
   transmitter meets the emission limitation requirements of  Sec. 73.44 is defined
   as a Class I permissive change for compliance with this section.

   (h) The interconnection of a multiplexing exciter with a certificated or
   formerly type accepted AM broadcast transmitter in accordance with the
   manufacturer's instructions without electrical or mechanical modification of
   the transmitter circuits and completion of equipment performance
   measurements showing the transmitter meets the minimum performance
   requirements applicable thereto is defined as a Class I permissive change
   for compliance with this section.

   (i) The addition of TV broadcast subcarrier generators to a certificated or
   formerly type accepted TV broadcast transmitter or the addition of FM
   broadcast subcarrier generators to a type accepted FM broadcast transmitter,
   provided the transmitter exciter is designed for subcarrier operation
   without mechanical or electrical alterations to the exciter or other
   transmitter circuits.

   (j) The addition of TV broadcast stereophonic generators to a certificated
   or formerly type accepted TV broadcast transmitter or the addition of FM
   broadcast stereophonic generators to a certificated or formerly type
   accepted FM broadcast transmitter, provided the transmitter exciter is
   designed for stereophonic sound operation without mechanical or electrical
   alterations to the exciter or other transmitter circuits.

   (k) The addition of subscription TV encoding equipment for which the FCC has
   granted advance approval under the provisions of  Sec. 2.1400 in subpart M and
    Sec. 73.644(c) of part 73 to a certificated or formerly type accepted
   transmitter is considered a Class I permissive change.

   (l) Notwithstanding the provisions of this section, broadcast licensees or
   permittees are permitted to modify certificated or formerly type accepted
   equipment pursuant to  Sec. 73.1690 of the FCC's rules.

   [ 63 FR 36600 , July 7, 1998, as amended at  66 FR 50840 , Oct. 5, 2001;  70 FR 23040 , May 4, 2005]