IBM 5280 User's Setup Procedures page 73

b. Position the cable so that the yellow label is on top; then push
the cable end into the socket .
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Note: If the cable end does not fit easily into the socket, be sure that
the connector guides line up with the socket guides.
c. Make sure that the snap-locks lock into position.
d. Repeat this procedure for the remaining diskette drive cables.
Note: Not all sockets (both data station and diskette drives) will be
used.
User's Setup Procedures 67