47 CFR 69.301: General.

(a) For purposes of computing annual revenue requirements for access elements net investment as defined in § 69.2 (z) shall be apportioned among the interexchange category, the billing and collection category and access elements as provided in this subpart. For purposes of this subpart, local transport includes five elements: entrance facilities, direct-trunked transport, tandem-switched transport, dedicated signaling transport, and the interconnection charge. Expenses shall be apportioned as provided in subpart E of this part.

(b) The End User Common Line and Carrier Common Line elements shall be combined for purposes of this subpart and subpart E of this part. Those elements shall be described collectively as the Common Line element. The Common Line element revenue requirement shall be segregated in accordance with subpart F of this part.