Figure 11-7 Top Exit access plates Figure 11-8 With and without FC 7917 11.3.3 Top or bottom exit cables  Features allow for Top Exit Cabling (FC 7917) or Bottom Exit Cabling (FC 7919) cabling, or a  combination of both. These features are independent of raised floor or non-raised floor  installations and offer flexible possibilities for the data center. All external cabling enters the rear of the rack from under floor or from above the rack.  Different from previous Z Systems, no cabling access or cable plugging is available at the  front of the rack. The top view of the rack with and without FC 7917 is shown in Figure 11-8.  The Top Exit Cabling feature provides new hardware. The new hardware resembles a  rectangular box with an open side that faces the front or rear of the rack. It includes other  hardware to organize and fasten cables. The Top Exit Cabling option can be used for routing power cables and IO cables out the top of  the machine. Without the Top Exit Cabling feature, power and cables still can be run out the top of the rack  through two adjustable openings at the top rear of the rack, as shown on the left side of  Figure 11-8. 466  IBM z15 (8561) Technical Guide