Thats the VHF Conventional freq.... They are also licensed for 155.29500 but I have never been told they used it there. They used to use it up in Rankin County, and over in LA where they are based.
They are primarily using the Jackson County TRS
As far as I know, all ambulance to ER is using the SERN on HEAR 155.3400. If there is an Hospital ER TG set on the TRS, it has never been submitted.
Same as it's pretty much always been. VHF is simulcast on Acadian 1. Nobody has ever made an conventional connection with "Acadian 2" (exactly what it's called, NOT tactical, all it is used for mostly is internal business and some occasional bsing) that I'm aware of, so I guess it's a dedicated TRS channel only. Either way both are highly annoying to me so I rarely ever listen to them.
155.34 is pretty much only ever used by LifeFlight 2. Even then not always. LF is the only ones you'll hear talking to a hospital too. I can only assume Acadian uses data links, or Southern Linc maybe, for patient confidential comms.
During the Winter storm we had over Friday, and then on Tuesday-Wednesday, the shift captain was using 'Acadian 2' on tkgp 1776 quite extensively to coordinate units from one location to another and so forth. There was quite a bit of traffic on that talkgroup.