The 4B/5B block coding discussed in Chapter 4 is a good example of this type of coding. In this coding scheme,
k = 4 and n = 5. As we saw, we have 2k = 16 datawordsand 2n = 32 codewords. We saw that 16 out of 32 codewords are used for message transfer and the rest are either used for other purposes or unused.