Digital Lightwave Inc. 40GS-G 40G SONET/SDH test option. PCS layer testing " Unframed PRBS BERT. " Analysis and generation of virtual lane skew. Support for: " SONET mappings supported: STS-768c/192c/48c/12c/3c/STS-1 Bulk mapping " SDH mappings supported: AU-4-256c/64c/16c/4c/C4/