Data acquisition (DAQ) electronics are described for a system of high-rate cathode strip chambers (CSC) in the forward region of A Toroidal LHC Apparatus (ATLAS) muon spectrometer. The system provides serial streams of control signals for switched capacitor array analog memories on the chambers and accepts a total of nearly 294 Gbit/s in serial raw data streams from 64 chambers in the design configuration. Processing of the data is done in two stages, leading to an output bandwidth of 2.56 Gbit/s. The architecture of the system is described, as are some important signal processing algorithms and hardware implementation details. Although designed for a specific application, the architecture is sufficiently general to be used in other contexts.