The ME3620A can access the Network Node Interface (NNI) of Synchronous Multiplexer/Demultiplexer systems in the world at 52, 156, 622, and 2488 Mb/s. The transmitter and receiver are housed in separate cabinets and can be operated independently. The analyzer has a variety of modules so the required measurement can be easily performed just by changing the module. In particular, a wide variety of optical sender units is available at 1.31/ 1.55 wavelengths, along with a wide variety of optical receivers and jitter units at various bit rates.