I know nothing about Cambria County, but I do know something about radios and the fire service. This is probably what they meant. "Returning (from call which we are currently on)Returning (to main dispatch channel). That would be my guess.
I know hear in Blair County many times fire units will say when they clear a scene or are placed into service that they are " available returning to fire dispatch" which means they are going off the opps channel and switching radio to dispatch channel . Sounds like that is what you may be reffering to.