IBM RT User's Setup Manual page 207

12. C onnect C-Dl on the cable bundle to the 20-pin connector on
the drive a d ap ter applicable to your system.
13. If your system uses the IBM RT PC Extended ESDI M agnetic
Media Adapter, set Ju m p er J 6 according to which slot the
adapter will occupy.
AJZIF067
2-32 Options Installation