AT&T System 75 Wiring Diagram page 166

Equipment Room Hardware And Cabling Installation
7.
Label connectors on each end of the cables that connect to the
switch cabinet.
8. Dress cables down the sides of the switch cabinet and store the
excess cable slack in the cable slack manager as described
previously.
Connecting Trunk Pairs to the Switch Cabinet Using Jumper Wires To
Establish 3-Pair Modularity
Figures 3-57 and 3-58 show trunk pairs connected to the switch cabinet
with jumper wires to establish 3-pair modularity. To connect the trunk
pairs to the purple field, proceed as follows:
1. Connect B25A connector cables between the network interface and
the sneak fuse panels (Figure 3-56).
2. Connect A25D/B25A connector cables from the sneak fuse panels
to the 110-type terminal block/66-type connecting block connectors
in the green field (Figure 3-56).
3. Connect 1-pair patch cords/jumper wires from each 110-type
terminal block row/66-type connecting block in the green field to
the 110-type terminal block rows/66-type connecting blocks in the
purple field as shown in Figure 3-57 for 1-pair CO trunks or in
Figure 3-58 for 3-pair tie trunks.
3-83