Epson Equity 320SX PLUS - Manual (Page 150)

The interface that protrudes from the back of the drive
has gold contacts on both sides. Near one end of the
interface, there is a gap to accommodate the plastic
divider on the connector.
Align the connector with the interface so that the plastic
divider on the connector lines up with the gap in the
interface, as shown below.
divider
Make sure the cable connector fits properly onto the
drive interface and then push it onto the interface. Then
go to step 8.
Caution
If you do not correctly align the connector, you could
severely damage your diskette drive when you push it
in.
7-22 Installing and Removing Disk Drives