Both current and future DWDM telecomm networks can be tested using the FTB-5240 Optical Spectrum Analyzer. The instrument's design provides data about signal levels, signal-to-noise ratio, crosstalk, channel spacing, and channel stability. The unit also delivers a wide spectral windows, excellent power and wavelength accuracy and a high optical rejection ratio of 50 dBc at 50 GHz. The novice can use the one-button testing capabilities while more experienced users can perform complex testing accurately. The software is dedicated to DWDM testing and can characterize any DWDM system or any building block of a system. The unit can be used at several stages, including manufacturing, pre-commissioning, commissioning, and maintenance. The test platform features a shock and waterproof casing, rubber bumpers, and protective panels for connectors, ports and floppy drives.