Seagate MEDALIST 17240 ST313030A - Manual (Page 24)

20 Medalist 17240, 13030, 10231, 8420 and 4310, Rev. B
Cable select jumper
Some computers differentiate between master and slave drives
using specially designed interface cables that have the line to pin
28 (the Cable Select pin) removed or cut at one connector. The
connector that has pin 28 disabled is used for the slave drive.
See your computer manual to determine whether your computer
supports this feature. To configure your Seagate drive for cable
select, place a jumper as shown on pins 5 and 6.