describe faulty yaesu documentation

git-svn-id: https://hamlib.svn.sourceforge.net/svnroot/hamlib/trunk@67 7ae35d74-ebe9-4afe-98af-79ac388436b8

ft847/README.ft847

@@ -22,8 +22,12 @@ Handles >90% of all opcodes
 Warnings
 --------
 
-NA
+1. FT-847 serial cable (DB9) is a null modem cable, unlike
+the FT747GX for example that uses straight cable to FIF-232C.
 
+2. Some of the documentation is faulty.
+	- TX and RX status descriptions are swapped.
+	- 
 
 Contributors
 ------------