The growth of T-carrier applications resident within an SDH signal is addressed by the latest ITU-T recommendations. Here, 1.544 and 44.736 Mbps have become important payloads which require testing. Another growing requirement is testing international gateways by switching 1.5 Mbps from SONET to SDH international connections. The SunSet SDH offers 1.544 Mbps Testing with fractional T1(Nx64 or Nx56 kbit/s) capabilities. 45M Testing also includes structured (channelized) testing with 1.5M or 2M payloads.