expandNCM[(h : NonCommutativeMultiply)[a___, b_Plus, c___]] :=
 Distribute[h[a, b, c], Plus, h, Plus, ExpandNCM[h[##]] &]

expandNCM[(h : NonCommutativeMultiply)[a___, b_Times, c___]] :=
 Most[b] ExpandNCM[h[a, Last[b], c]]

expandNCM[a_] := ExpandAll[a]

compressNCM[expr_] := expr /. NonCommutativeMultiply[x__] :>
   StringJoin@(ToString /@ {x})

toNCM[expr_] :=
 expr /. str_String :>
   NonCommutativeMultiply @@ (ToExpression /@ Characters[str])

encm = expandNCM[(a ** b + c ** d) ** (e ** f + g ** h)]

% // compressNCM

encm == % // toNCM