The Tektronix ST2400A is the first STM-16/OC-48 test product optimized for testing 2.488 Gbit/s Dense Wave-length Division Multiplexed (DWDM) client systems. Its compact size, flexibility of configuration, choice of operating modes, unique I/O features, extensive software driver support, and range of error and defect inject capabilities make it particularly effective for DWDM system test during production and installation. It can also be used in non-DWDM SDH and SONET test applications. The Tektronix ST2400A is payload-independent; external SDH/SONET 155 Mbit/s optical and electrical and 622 Mbit/s optical signals are supported in add/drop mode. The ST2400A can be ordered as an ST2400A Transceiver, as an ST2400R Receiver, or as an ST2400T Transmitter to meet a wide range of application needs economically.