+XGOKBD = $52
+
+; Buffer management
+XECRBU = $54 ; Write A or AY in the buffer
+XLISBU = $55 ; Read A or AY in the buffer
+XTSTBU = $56
+XVIDBU = $57 ; Flush the buffer
+XINIBU = $58 ; Initialize the buffer X
+XDEFBU = $59 ; Reset all value of the buffer
+XBUSY = $5A ; Test if the buffer is empty
+