154.220 is used for dispatching. I'm not an expert on this topic, but I do know that on this particular type of trunk system it is not possible to dispatch via a talk group, as it will not set off the firemen's pagers. I don't know if this applies to all trunk systems because I have seen talk groups labeled "Dispatch" on other systems but I don't know how it works. In the case of Burlington County, however, it's all done via 154.220.