47 CFR § 32.2212 - Digital electronic switching.
(a) This account shall include the original cost of stored program control digital switches and their associated equipment. Included in this account are digital switches which utilize either dedicated or non-dedicated circuits. This account shall also include the cost of remote digital electronic switches. The investment in digital electronic switching equipment shall be maintained in the following subaccounts: 2212.1 Circuit and 2212.2 Packet.
(b) This subaccount 2212.1 Circuit shall include the original cost of digital electronic switching equipment used to provide circuit switching. Circuit switching is a method of routing traffic through a switching center, from local users or from other switching centers, whereby a connection is established between the calling and called stations until the connection is released by the called or calling station.
(c) This subaccount 2212.2 Packet shall include the original cost of digital electronic switching equipment used to provide packet switching. Packet switching is the process of routing and transferring information by means of addressed packets so that a channel is occupied during the transmission of the packet only, and upon completion of the transmission the channel is made available for the transfer of other traffic.
(d) Digital electronic switching equipment used to provide both circuit and packet switching shall be recorded in the subaccounts 2212.1 Circuit and 2212.2 Packet based upon its predominant use.
(e) Switching plant excludes switchboards which perform an operator assistance function and equipment which is an integral part thereof. It does not exclude equipment used solely for the recording of calling telephone numbers in connection with customer dialed charged traffic, dial tandem switchboards and special service switchboards used in conjunction with private line service; such equipment shall be classified to the particular switch that it serves.