@Joe: I don’t have any experience with FT8. However, I think you need to be in digital (DIG) mode on the radio in order for it to “listen” on the data in pin. Check out page 63 of the manual: http://www.yaesu.com/downloadFile.cfm?FileID=654&FileCatID=158&FileName=FT%2D857.pdf&FileContentType=application%2Fpdf