Sentence:  The data word processor 606 handles the in-flow and out-flow of byte-oriented input/output data and interleaved signals at a rate of, for example, 500 <WSD>kilobytes</WSD> per second. Instruction processing rates of four to eight per microsecond are required for such a data flow. 
Meaning of the word marked with <WSD> tags:  1000 (103) bytes. SI Symbol: kB