Only codes we use here are:
Code 2 (no lights or sirens, driving like normal)
Code 3 (using lights and sirens, can drive thru red lights once traffic has yielded, oppose traffic (driving on the opposite side of the roadway), etc)
Code 4 is "Clear to enter". Pretty much only used for where we are staging out for Law Enforcement, such as assaults, shootings, stabbings, etc. Code 4 means they're on scene in control and we can then safely enter the scene.
Status 5 is about the only code we use regularly that's not common elsewhere (as far as I know at least, only we use it). Basically means we're finishing up at the hospital after a transport, getting ready to clear. So if I'm at the hospital in my district and someone else is moving up to my area for coverage, while I'm not fully available yet, dispatch should* let the other crew start returning to their own area. Technically they want us to go Status 5 as soon as we move the patient off of our gurney onto the hospital equipment (hosp bed, chair in triage waiting area...) and then go available within 5 minutes, but because sometimes it takes longer than that to actually get a nurses signature, plus actually having to deconstruction and redress the gurney, clean up any mess in the patient compartment, we don't usually do that until all that is done and my partner has returned to the rig and is just finishing up paperwork (and what do you know, oftentimes that's quickly enough we can skip status 5 and just go available lol). Doesn't help that some dispatchers forget the difference between status 5 and available and will try to give you post changes or even calls when we're not actually quite ready to respond yet.
Everything else we just use plain English (responding, on scene, transporting, at hospital, clear, etc)