What must all VDV circuits do before being placed in service?

All VDV (Voice, Data, and Video) circuits are required to be tested and certified to meet minimum industry standards before being placed in service to ensure reliability, safety, and performance. This testing verifies that the circuits operate as intended within the specifications set by relevant standards, helping to prevent potential failures or issues in the future. Proper certification demonstrates compliance with these industry standards, such as those from organizations like TIA (Telecommunications Industry Association) or ISO (International Organization for Standardization), thus ensuring that the installation is robust and capable of supporting the intended applications effectively.

The other options suggest actions that do not establish the foundational requirement for circuit readiness. For instance, using a circuit for live data transmission or monitoring it in real-time are operational aspects that come after testing and certification, while assembling the circuit solely with fiber optic cables does not address quality assurance and compliance with standards, which is critical before any operational use.