Pretty sure he'd be smart enough to know how to send a communication to some device he made that he planted on Light or something. :P

Rmember Shockwave is supposed to be smart, so make him smart. The show doesn't make him smart because then he'd be a threat, which the decepticons aren't. (And tbh if the military was competent no cybertonians in their current forms would ever be threats. Nukes witheld, one spec ops with a few kg of C4 could beat any of them.)