It was, but what was being communicated was recorded or transmitted data (computer files and images) between tricorders and various information systems rather than voice transmissions. There have been plenty of times in which tricorders were used to download files from a non-Enterprise computer system or device.
Earlier in this thread we were discussing why the tricorders and communicators weren't combined. While researching some prop photos, I came across a screen used hero tricorder used in DS9, Voyager, First Contact, and Insurrection that had sold at auction. From the photos, specifically the one I included above, it seems there was some level of integration of communicators and tricorders. Wonder why that was never established onscreen?
