This configuration places a cross-over connection between the two connected devices upon failure, ensuring the connection remains continuous. Without the cross-over connection between the two devices, it disrupts because the ZPHA is completely passive, only passing signal from pin to pin. See Figure 2 - 12, “ZPHA Cross-over Configuration 3 and Figure 2 - 13, “ZPHA Cross-over Configuration 4.
Figure 2 - 12: ZPHA Cross-over Configuration 3
UnityOne Modular Fiber/Copper ZPHA Installation Guide V 2.1
