Before the county was on any trunked system some county services like haz-mat and OEM where on 155.5500 for operations while others used 477.2875,some towns on UHF had this frequency. Then when the trunked system first starting coming on the air 155.5500 and 477.2875 became ways towns could talk to the county, and county units, without having access to the trunked system. Now it seems the frequencies are both stand alone, meaning each can be used separately, can be patched together meaning what comes out on 477.2875 can go put on 155.550 and vice versa OR patched to to a talkgroup on the trunked system depending on what's needed. In theory *any* talkgroup on the system can be patched to either, or both frequency.