The XRT86SH221 (Voyager-Lite) is a physical layer SDH to PDH mapper/demapper which enables E1 aggregation to STM-1 via standard VC-12 to AU-3 and TUG-3/AU-4 mapping protocols. Voyager-Lite supports all the framing, mapping and grooming functions required for STM-1 mapper applications. The device generates and terminates all SDH Regenerator Section, Multiplexer Section and Path Overhead including the low-order Virtual Container (VC) Path Overhead. E1 framing is transparent; therefore, the device neither generates nor terminates the E1 frame.