Thanks Will, that I know well. Actually grew up in Hinsdale.Hinsdale PD is dispatched by Southwest Central Dispatch in Palos Heights. They are on Net 9 which is 476.7375 MHz PL 114.8; They are the 2800 series units. Net 9 also includes Clarendon Hills 4000's, Willowbrook 1500's, Burr Ridge 4400's, Indian Head Park 4100's, and Lemont 3800's PD's.
Hinsdale FD is dispatched by Southwest Central Dispatch on 153.635 MHz PL 146.2 Hz. They are the 1000 units, along with Clarendon Hills FD 300 units, and Tri-State FD 500 units. Tri-State dispatches themselves.
I hope this helps.