Systems and methods for point-to-multipoint communications with CAS are provided. In one embodiment, a line unit comprises: an interface to communicate with a node using a first frame structure comprising timeslots, the frame structure transporting signaling bits in an x'th timeslot; the unit coupled another line unit via a communication link, wherein the other unit communicates with another network node using a second frame structure comprising timeslots, the second frame structure transporting signaling bits via its x'th timeslot. Payload timeslots for a first frame received from the other line unit are mapped from the second frame structure to payload timeslots of a second frame using the first frame structure and transmitted via the interface. The x'th timeslot for each of the first and second frame structures are formatted in a multiframe structure comprising a schedule of signaling bit locations allocated to signaling bits corresponding to a designated payload timeslot.