The TAC provides features, selected by the subscriber, to all edge switches connected to the PSTN tandem switch.

Thus, not only the delay time is shortened, but also only the subscriber's switch directly accommodating the user may have the functions concerning the protocols used by the user, simplifying the hardware structure such as a repeating switch.

iv) connection of a CNCP switch to a telephone company local tandem switch (similar to a Type 1 connection as defined in Decision 79-11); and