Keith,
The above information for programming regarding Butler Simulcast Site is correct but I wanted to provide some operational context to help you listen to Oxford area police and fire traffic.
Butler County Communications Center (9COM) uses four primary law dispatch talkgroups on the BRICS trunked system: 9179 - 09 ZULU, 9180 - 09 ECHO, 9170 - 09 TANGO, and 9079 - 09 DELTA. They use two primary fire talkgroups: 9139 - 09 ALPHA and 9130 - 09 BRAVO. All primary dispatch talkgroups on the BRICS system are clear (not encrypted)., Please note that I am doing this from memory so the HECs may not be accurate because of reassignments after the closure of Hamilton and Oxford dispatch centers.
BRICS has changed talkgroup assignments several times over the years to better distribute the workload for 9COM. Under the current plan, both Oxford City and Oxford Township police are assigned to DELTA. DELTA is usually patched with ZULU, which is the Sheriff's Office and smaller townships and villages, but is separated during busy times in Oxford. I have heard of folks listening to OPD on ZULU (via the patch with DELTA) and then not hearing them because they don't actually have DELTA programmed in. Oxford was assigned to ZULU in a previous programming configuration which has caused some of this confusion.
9COM fire setup is somewhat simpler. ALPHA is westside agencies, including Oxford and College Corner, and BRAVO is eastside agencies, including Hamilton. These two are almost always patched but can separate in cases such as extreme weather that causes many minor runs. These talkgroups handle status changes of units only as fireground operations occur on a common FIRE talkgroup. Initial fire dispatching can be heard on 9149 - 09 FD DISP which has no field unit talkback.
So a long explanation to basically tell you to make sure you are listening to DELTA and ALPHA and you will hear Oxford area police and fire traffic. I would also listen to FD DISP as well as the LAW, FIRE and TAC talkgroups as Oxford uses these regularly, especially for incidents involving Miami University PD.
I hope this helps.