How to check if the communication network is grounded at only 1 point?

In a communication network, the shielding of the mesh is grounded in only 1 point to avoid possible current circulations that interfere with the serial communication of the equipment. To verify this grounding, the following test is performed:

1. Remove the grounding point from the earth network.

2. The continuity from the ground point (previously disconnected) to the ground is measured with a multimeter.

If the mesh is grounded at only 1 point, there will be no continuity; otherwise, check the installation where there are other grounds.