During some emergency situations, the phone system will be destroyed especially when there is a building collapse. What can we do to protect the phone line?

Use a separate single-cable phone line not part of the buildings main phone  system, Place the telephone wire into a metal conduit, and having the cable enter/exit the building at the lowest level of the building.

Explanation:

on june 23, 1972, the president signed title ix of the education amendments of 1972, 20 u.s.c. into law. title ix is a comprehensive federal law that prohibits discrimination on the basis of sex in any federally funded education program or activity.