66 2. Mobile petitioners next challenge the Commission’s understanding of “interconnected service.” That term, too, is an integral part of the definition of commercial mobile service. A commercial mobile service must “make[] interconnected service available . . . to the public or to . . . a substantial portion of the public.” 47 U.S.C. § 332(d)(1). And “interconnected service” is “service that is interconnected with the public switched network.” Id. § 332(d)(2). As with the phrase “public switched network,” Congress gave the Commission express authority to define the term “interconnected service.” Id. The Commission has defined “interconnected service” as a service “that gives subscribers the capability to communicate to or receive communication from all other users on the public switched network.” 47 C.F.R. § 20.3 (prior version effective through June 11, 2015); see 2015 Open Internet Order, 30 FCC Rcd. at 5779 ¶ 390. (We note that, in the 2015 Order, the Commission excised the word “all” from that definition. But as we explain below, the Commission considered that adjustment a purely conforming one with no substantive effect; we use the prior language to confirm that mobile broadband would qualify as interconnected service regardless of the Commission’s adjustment.) The question under the Commission’s definition of “interconnected service,” then, is whether mobile broadband “gives subscribers the capability to communicate to or receive communication from all other users on the public switched network” as redefined to encompass devices using both IP addresses and telephone numbers. 47 C.F.R. § 20.3 (prior version effective through June 11, 2015). The Commission reasonably found that mobile broadband gives users that