47 CFR § 51.325 - Notice of network changes: Public notice requirement.
(1) Will affect a competing service provider's performance or ability to provide service;
(2) Will affect the incumbent LEC's interoperability with other service providers; or
(3) Will result in a copper retirement, which is defined for purposes of this subpart as:
(i) The removal or disabling of copper loops, subloops, or the feeder portion of such loops or subloops; or
(ii) The replacement of such loops with fiber-to-the-home loops or fiber-to-the-curb loops, as those terms are defined in § 51.319(a)(3).
(b) For purposes of this section, interoperability means the ability of two or more facilities, or networks, to be connected, to exchange information, and to use the information that has been exchanged.