In Gwinnett county, engines, trucks, and med units paged via station # for their specific area. The two closest to me are Station 26 (one engine), and Station 14 (engine, truck, and ems unit). Also nearby is Station 24 behind the Mall of GA. They are part of Battalion 3. Only on large fires is the battalion chief called out. Pretty much the same for all other areas I monitor in the north metro area.
HTH,
Larry