The N4876A 28 Gb/s Multiplexer allows to extend the generator data rate of the J-BERT N4903B and ParBERT 81250A up to 28.4 Gb/s. Design and test engineers in the semiconductor, communications, storage and computer industry can now accurately characterize the next generation of serial interfaces operating at bit rates of up to 28.4 Gb/s. With its excellent output performance it helps to optimize design margins by minimizing the influence of the test equipment on measurement results. The small size allows to locate the device under test closely to the outputs. The N4876A multiplexer doubles the pattern generator data rate by multiplexing two pattern generator channels. The N4876A extends the variable generator data rate of J-BERT N4903B up to 28.4 Gb/s and of ParBERT 81250A up to 27.0 Gb/s. It's an affordable path to extend the operating rate up to 28.4 Gb/s by just adding the multiplexer front-end to a 12.5/13.5/14.2 Gb/s BERT pattern generator.