Siemens TransXpress is a family of SDH transport multiplexers—such as the SMA1K, SMA4, SMA16/4, SL16, SL64, and SXA/SXD cross-connect units—designed for high-reliability metro and backbone networks. These systems support STM-1 to STM-64 transmission, with flexible add/drop and cross-connect capabilities and optional Ethernet integration. Carritech provides full support for the TransXpress range, including spare parts, repairs, refurbishment, and technical assistance to help operators maintain and extend the life of their legacy SDH infrastructure.