IBM 5280 User's Setup Procedures page 71

5. Read the following four steps (a, b, c, and d) before
connecting the data station cable.
a. Find a cable connector with a green label. Read the identification
label.
For example, if you find a cable with the following label, this cable
connects to socket 0 on the 5288.
Data Station ca~ble
Machine Type XXXX
Location - - -
Socket
JL
From the 5281 or 5282
To Socket 0 on the 5288
b. Position the cable so that the green label is on top; then push
the cable into the socket.
Green Label
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.
User's Setup Procedures 65