IBM RT PC Options Installation page 75

TNL SN20-9864 (May 1987) to 75X0217
10. Connect the cable bundle to the drive adapter applicable to
your system:
2-36 Options Installation
• If you are installing an R40 or R70 fixed-disk drive, connect C-E
and C-El of the fixed-disk and diskette drive second cable bundle
as shown.
Second Cable