Bonding the shield to the _____ will reduce noise level in the telecommunications cable.

Bonding the shield to the ground is essential for reducing noise levels in telecommunications cables. The shield serves as a barrier that helps prevent external electromagnetic interference (EMI) from affecting the signals transmitted within the cables. By connecting the shield to the ground, any unwanted noise that may couple onto the cable can be safely directed away from the signal path and discharged into the ground. This grounding connection creates a path for the interference to dissipate, thereby enhancing the performance and reliability of the telecommunications system.

In options such as a transformer, router, or switch, while these components are critical in the overall telecommunications infrastructure, they do not have the same direct role in noise reduction through shielding as grounding does. A transformer is primarily used to change voltage levels, routers direct network traffic, and switches connect devices within a network. None of these address the issue of EMI reduction as effectively as grounding the shield does. Therefore, securing the shield to the ground is the most effective strategy for noise reduction in telecommunications cables.