Software Configurable Telecommunication Transmission Network System is a second generation SDH product to integrate STM-1 Add/Drop Multiplexer, Terminal Multiplexer and Regenerator on a single module providing VC-4, VC-3 and VC-12 connectivity. The Network System is used for junction and regional telecommunication transmission networks based on the most recent standards and recommendations on SDH from ITU-T and ETSI. The Network System is designed with equipment that supports integrated engineering order wire facility with omnibus and selective calling functionality. Software Configurable Telecommunication Transmission Network System also supports a dedicated user data channel for auxiliary functions.