DISC is "DATA out 9600" this is audio from the discriminator (in an FM radio).  It is what some call "Flat Audio" with no pre-emphasis filtering.
AF is "Data Out 1200" this is shaped audio which has been filtered and would be typical of what one would hear on a speaker or headphones.

AF is fine for analog and many of the HF data modes and traditional AFSK packet.  DISC is used in more sophisticated modulation schemes such as GMSK.  If your radio doesn't have a one-to-one matching socket, then a cable must be made to go to equivalent points on your radio.  One would look at available connection points on their radio, usually a socket of some sort, and make a cable that matches them up.  There are diagrams for various radios on the Internet and there are people who make them, like https://hammadeparts.com who will fabricate them.

You will note on DRAWS™ Manager (http://localhost:8080 on your DRAWS™) a tool to help select AF/DISC connectivity for a radio.

BTW, the discussion group https://nw-digital-radio.groups.io/g/udrc/ is the correct venue for DRAWS™ and UDRC topics.