A communication system comprises a first communication unit having a plurality of application ports; and a second communication unit having a plurality of application ports and coupled to the first communication unit; wherein the first communication unit is configured to extract timeslots from a first signal having a first interface format and from a second signal having a second interface format, and to insert the extracted timeslots into a frame for transmission to the second communication unit; wherein the second communication unit is configured to pass the first interface format signal to an application port of a similar interface format and to pass the second interface format signal to an application port of a third dissimilar interface format based on the order of the extracted timeslots in the frame transmitted from the first communication unit.