Robert, There is no interface cable for MFJ-998 and FLex of any vintage.. Other than you can route a PA PTT signal through the 998 to inhibit a PA while the 998 is tuning.. I no longer have my 998, but when I did, I was able to do a bit more integration using DDUtil ( between the 998 and PowerSDR ) and a bit of ingenuity to almost achieve tune cycle operation ( i.e. click a button in DDUtil to key the radio and start the tune cycle, automatically terminate the tune cycle when tuning was complete. ) The 998 has no provisions for tracking the operating frequency other than its own built in frequency counter. I was not totally happy with the operation but that was more a limitation of the 998 than Flex/DDUtil.