A data coupling arrangement for successively receiving, in parallel, nibbles of respective data words, each nibble having a value, and for selectively coupling nibbles associated with one word in response to the relative values of the words. The selective coupling is determined by an identifier indication. The identifier indication is generated in response to a selected relationship between values represented by the nibbles from the respective words, until after nibbles are received whose values differ. At that point, the identifier indication is maintained in its condition thereby enabling the transfer of nibbles subsequently received from the same data word.