The Federal Communications Commission adopts a location-based definition of ``primary residential line.'' Under this definition, one residential line that a price cap local exchange carrier (LEC) provides to a particular location will be considered primary. Any other residential lines the price cap LEC provides to the same location shall be deemed non-primary residential lines. The Commission maintains the existing definition of ``single line business line.'' These definitions will facilitate implementation of the Commission's access charge rules, which set higher caps for the subscriber line charges (SLCs) and presubscribed interexchange carrier charges (PICCs) that price cap LECs may assess on non-primary residential lines and multi-line business lines than on primary residential lines and single line business lines. Adopting requirements for differentiating and identifying such lines will promote uniformity in the way price cap LECs assess SLCs and PICCs.