1. A data compression/transfer/decompression system operating to transfer a stream of data, which may be designated n=1, 2. .. N-1, N and repeating n=1, 2. .. N-1, N, compressed according to a selected data compression model, characterized by (a) data input means; (b) first state generator means (b), connected to said data input means (a), for providing a binary decision bit signal for binary decision n, and a state signal, which may be a multi-bit signal, for binary decision n; (c) first adaptive probability generator means, connected to said state generator means (b), responsive to a previously developed statistic value developed during binary decisions 1. .. (n-1), to state signal n and to bit signal n to provide an updated probability statistic for use in decisions subsequent to binary decision n, and to provide probability signal n as output; (d) coder means, connected to said first state generator means (b) and to said first adaptive probability generator means (c), responsive to state signal n and binary decision bit signal n provided by said first adaptive probability generator means (c), to generate a compressed data group for transfer; (e) transfer means connected to said coder means; (f) decoder means, connected to said transfer means (e), to second state generator means (h) and to second adaptive probability generator means (i), responsive to a compressed data transfer signal group, to destination state signal n and to destination adaptive probability signal n to provide decompressed signals for binary decision n; (g) output means, for providing at the destination a data stream of decompressed data corresponding to the data stream at said input means,; (h) second state generator means, connected to said output means (g), to said decoder means (f) and to second adaptive probability generator means (i), providing for binary decision n, a destination state signal n, which may be a multi-bit signal, and responsive to said decoder output destination bit signal n to provide output data to said output means (g); (i) second adaptive probability generator means, connected to said second state generator means (h) and to said decoder means (f), responsive to said destination bit signal and to said destination state n to provide an updated probability statistic for use in decisions subsequent to binary decision n, and to provide probability signal n as output.