The link below goes through how to set up RTTY and N1MM for Flex 6000:
https://file.notion.so/f/s/9216f396-e9a2-4057-97c7-2545abf06510/Operating-RTTY-and-N1MM-for-the-FLEX-6000-How-to-Guide.pdf?id=93ececb2-486c-4ae2-9127-7ac0852ebe12&table=block&spaceId=464c012b-bb97-4aca-b41b-64d313ce94da&expirationTimestamp=1699113600000&signature=ulZYR2CsKZrzFG6_aevVZMq2kNnEnWjEFMzNk_NpwnA&downloadName=Operating-RTTY-and-N1MM-for-the-FLEX-6000-How-to-Guide.pdf