UNE-EN 301165 V1.1.3:2005 Transmission and Multiplexing (TM); Synchronous Digital Hierarchy (SDH); SDH leased lines; Network and terminal interface presentation (Endorsed by AENOR in November of 2005.)
2020UNE-EN 301165 V1.1.2:2020 Transmission and Multiplexing (TM); Synchronous Digital Hierarchy (SDH); SDH leased lines; Connection Characteristics (Endorsed by Asociación Española de Normalización in June of 2020.)
2007UNE-EN 301165 V1.1.1:2007 Transmission and Multiplexing (TM); Synchronous Digital Hierarchy (SDH); SDH leased lines; Network and terminal interface presentation (Endorsed by AENOR in November of 2007.)
2005UNE-EN 301165 V1.1.3:2005 Transmission and Multiplexing (TM); Synchronous Digital Hierarchy (SDH); SDH leased lines; Network and terminal interface presentation (Endorsed by AENOR in November of 2005.)