The present invention is a switching system interface providing conversion between time-division multiplexed digital signals and packetized digital signals used to bypass a common control and switch matrix of a class 5 digital switch. The switching system interface includes a network interface for terminating a digital transmission facility that is part of a network architecture. In addition, the interface includes a line/trunk interface, compatible with the internal signals used to operate the line/trunk interface of the class 5 digital switching system and a switch, connected to the network interface and to the line/trunk interface, for routing data between network interfaces and line/trunk interface. The interface also converts the data between time-division multiplexed digital signals and packetized digital signals.