OK, thank you.
Something else now (Or should I open another post ?) : Applesoft was not able to handle Hex values so I translated $xx into decimal via a subroutine. With C64 and X16, I can write POKE $xxxx, $yy but what if I use DATA ?
10 DATA $1000, $FF
20 READ A$, D$
30 A = VAL(A$) : D = VAL(D$) : REM DOES NOT WORK !!!!!
40 POKE A, D : REM WILL POKE $00 INTO ADDRESS $0000 !!!
40 PRINT A, D : REM IS SAFER