What kind of cable should I use for connecting to the display to the main BUS line?
A twisted pair Cat. FTP cable. 5e scheme for data, and if it also has voice coms, 2 pairs of another Cat. FTP cable 5e screen for Voice and Announcements. Alternatively, you can use a single cable type S/STP Cat.5e (4 twisted pairs individually sheathed). Power on a separate 2 x 2.5 mm² cable.