While I could see the appearance and internal mechanisms of Odo's communicator being copied, I do find the idea that Odo can emit signals and be networked with various ships'/stations' computer systems hard to accept. I assume there's some software involved.
Totally. But then he is a flat deck plate, or gloops out of one, badge and all, and there’s just no other explanation. You can explain it being taken off of him (haircut) and pray to the gods of handwavium when he doesn’t just make another one (handwavium is definitely in the pantheon of many fandoms) but when there’s no telltale lumps bumps or tinkle sounds, and he’s busy pretending to be ‘you are here’ on the promenade (some days he probably just screws with tourists) before popping up, then there’s no choice. And once there is no choice, it becomes part of the world building and character. Changelings are living replicators at the end of the day.
Can you imagine the stories about changelings that stayed so deep in cover that they had to wait for nature to take its course after they disguised themselves as a jum’ja stick? Or that time never to be spoken of again where Odo spent too long as a bottle of Kanar on a stag-do in Quarks? XD