Abstract: In accordance with the invention, an interface between an incumbent local exchange carrier's central office terminal and a competitive local exchange carrier's remote terminal is provided by an Integrated Services Digital Network interconnection. Such a connection provides two basic data channels of 64 Kbps each and at least one utility channel. The ISDN signal can be carried over a single wire pair. The interface may be used to interconnect one or two digital channels. The channel units may be designed to remove the robbed bits from the data channels and place them in the utility channels. Further, the utility channel may be employed to transmit frame phasing information so that the networks can synchronize their robbed bit signaling so that both networks use the same bit positions for robbed bit signaling thus minimizing data bandwidth reduction due to robbed bit signaling.