AT&T 75 Wiring Manual page 269

Each 110 label is used to identify 2 rows on the 110 terminal block. The upper half of the
label identifies the row above it and the lower half of the label identifies the row below it.
The labels slide into the clear plastic designation strips (Figure 3-34) that come with the 110
terminal blocks. The designation strip snaps into place between the 110 terminal block rows
after the label has been inserted. Label code number 220A (comcode 103 970 000) contains
all of the 110 labels.
Figure 3-34. Clear Plastic Designation Strip
110-TYPE HARDWARE
3-53