Like I said in another thread just now:
Why not use a telephone with a load speaker?
Simple, understandable and commonly used by most other Maritime Nations.
But then again; why make it simple when you can do it the American way??
That’s basically what an internal net is, with a speaker being both in CIC and the bridge. You just use Push To Talk(either a foot pedal or a button on the phone) and are talking to the other stations.
And most all of the comms internally are done via plain language to avoid foul-ups.