User guide

Rack Installation Guide 1-23
Figure 1-13. Two-Post, Open-Frame Relay Rack Universal-Hole Spacing
Wide-Hole Spacing Racks
Some two-post racks with wide-hole spacing have an alternating pattern of two holes per U with
center-to-center hole spacing (beginning at the top hole of a 1-U space) of 31.7 mm and 12.7 mm
(1.25 inches and 0.5 inch) for the front and back vertical column of holes (see Figure 1-14).
Figure 1-14. Two-Post, Open-Frame Relay Rack Wide-Hole Spacing
44 mm 1.75 inches (1 U)
15.9 mm (0.625 inch)
12.7 mm (0.5 inch)
15.9 mm (0.625 inch)
15.9 mm (0.625 inch)
44 mm (1.75 inches) (1 U)
12.7 mm (0.5 inch)
31.7 mm (1.25 inches)