47 C.F.R. § 36.321
(a) The expenses related to central office equipment are summarized in the following accounts:
| Central Office Switching Expense | Account 6210. |
| Operator Systems Expense | Account 6220. |
| Central Office Transmission Expense | Account 6230. |
[52 FR 17229, May 6, 1987, as amended at 69 FR 12552, Mar. 17, 2004; 83 FR 63586, Dec. 11, 2018]