Subcategory 1.1-State Private Lines and State WATS Lines. This subcategory shall include all private lines and WATS lines carrying exclusively state traffic as well as private lines and WATS lines carrying both state and interstate traffic if the interstate traffic on the line involved constitutes ten percent or less of the total traffic on the line.
Subcategory 1.2-Interstate private lines and interstate WATS lines. This subcategory shall include all private lines and WATS lines that carry exclusively interstate traffic as well as private lines and WATS lines carrying both state and interstate traffic if the interstate traffic on the line involved constitutes more than ten percent of the total traffic on the line.
Subcategory 1.3-Subscriber or common lines that are jointly used for local exchange service and exchange access for state and interstate interexchange services.
47 C.F.R. §36.154