And even luckier if all three actually work Pip!
As a BA instructor we teach 'communications', which in part is about how to use a radio (when you've got a set on you need to speak directly into the handpiece of the radio, rather than across it like you normally would, as the voice is projected forward from the mask) but apart from that you're right there is no radio comms per se, as someone else said at a reaccred you've been there for a while and I would hope you've done some radio stuff with your brigade by then. But then we should never assume anything should we! I'm all for training how we play and if that means crews go in with a radio where available during reaccreds then bring it on.
Its true that we're taught the first thing you do when you hear a DSU is CONTACT IOC AND NOTIFY THEM and this either means via radio or you get the hell out and let some one know, rather than attempting to cross through the building to locate the DSU. It may be that the DSU that has been activated can be safely snatched through a window, which the IOC will be able to assess, but those inside may be walking directly into trouble. Hard to say really, would need to weigh up the sitation - complexity of the building, how advanced the fire is, visibility, crew availability outside (yes, not all of us are flushed with resources, some CFS brigades not only don't have radios to go around, they don't have another back up BA crew for another ten or so minutes)...
I've heard people say that if they came across a heavy casualty that they would activate their DSU to bring in support crews... Radios are a much better option but I've rarely been in the situation where we've had enough to go around on a fire ground.
