Which of the following should NOT be implemented to protect PBX’s?(Choose all that apply)

A.
Change default passwords and configurations

B.
Make sure that maintenance modems are on 24/7

C.
Review telephone bill regularly

D.
Block remote calling after business hours
E. Post PBX configuration and specs on the company website

Explanation:
Many vendors have maintenance modems that vendors can use to troubleshoot
systems and provide updates. They should normally be turned off. Also information about the
system should not be posted on the website and should be closely guarded.