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VDF
Vertical Distribution Frame is the cable going out to the SAC/JWI or directly to the
Demarcation point. A component at the VDF is the protection unit: fuses or other devices
that protect the switch from lightning, shorts with electric power lines, or other foreign
voltages coming from the Outside Plant (OSP).
Figure 9: VDF Vertical Frame
The cable leaving the Central Office to the SAC/JWI is known as the Feeder Cable, some areas call it
F1.
Figure 10: Central Office Horizontal Frame (Left) & Vertical Mounted IDF frame in CO (Right)