Sec. 2.1001  Changes in type accepted equipment.

    (a) Equipment of the same type is defined for purposes of type 
acceptance as being equipment which is electrically and mechanically 
interchangeable and in addition will have the same basic tube or 
semiconductor lineup, frequency multiplication, basic frequency 
determining and stabilizing circuitry, basic modulator circuit and 
maximum power rating. Variations in electrical and mechanical 
construction, other than the items indicated above are permitted 
provided the variation or change is made in compliance with the 
requirements of paragraphs (b), (c), and (d) of this section.
    (b) Two classes of permissive changes may be made in type accepted 
equipment without requiring a new application for and grant of type 
acceptance.
    (1) A Class I permissive change includes those modifications in the 
equipment which do not change the equipment characteristics beyond the 
rated limits established by the manufacturer and accepted by the 
Commission when type acceptance is granted, and which do not change the 
type of equipment as defined in paragraph (a) of this section. No filing 
with the Commission is required for a Class I permissive change.
    (2) A Class II permissive change includes those modifications which 
bring the performance of the equipment outside the manufacturer's rated 
limits as originally filed but not below the minimum requirements of the 
applicable rules, and do not change the type of equipment as defined in 
paragraph (a) of this section. When a Class II permissive change is made 
by the grantee, he shall supply the Commission with complete information 
and results of tests of the characteristics affected by such change. The 
modified equipment shall not be marketed under the existing grant of 
type acceptance prior to acknowledgement by the Commission that the 
change is acceptable.
    (3) When a Class II permissive change is made by other than the 
grantee of type acceptance, 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.
    (c) A grantee desiring to make a change other than a permissive 
change as described in paragraph (b) of this section 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(s) is authorized.
    (d) If the Commission authorizes the changes requested, it may 
require the assignment of a new FCC Identifier.
    (e) Users shall not modify their own equipment except as provided by 
paragraphs (b) and (f) of this section.
    (f) Equipment 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.

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    (5) The station licensee shall be responsible for insuring that 
modified equipment used at his station will comply with the applicable 
technical standards in part 97 of this chapter.
    (g) The interconnection of a type accepted AM broadcast stereophonic 
exciter-generator with a 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 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 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 type 
accepted TV broadcast transmitter or the addition of FM broadcast 
stereophonic generators to a 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 type accepted transmitter 
is considered a Class I permissive change described in paragraph (b)(1) 
of this section.
    (l) Notwithstanding the provisions of this section, broadcast 
licensees or permittees are permitted to modify type accepted equipment 
pursuant to Sec. 73.1690 of the FCC's Rules.
[ 39 FR 5919 , Feb. 15, 1974, as amended at  39 FR 27803 , Aug. 1, 1974;  41 FR 19948 , May 14, 1976;  43 FR 12687 , Mar. 27, 1978;  46 FR 18981 , Mar. 
27, 1981;  48 FR 56391 , Dec. 21, 1983;  49 FR 27147 , July 2, 1984;  49 FR 34014 , Aug. 28, 1984;  51 FR 2707 , Jan. 21, 1986;  51 FR 39535 , Oct. 29, 
1986;  51 FR 41628 , Nov. 18, 1986]