Question: What’s demarcation points anyway?
Answer: The term “demarcation points” (also called demarc), is the point within a facility, property or campus where a circuit provided by ISP or Telecom, terminates. Past this point, the customer must provide equipment or further vertical & horizontal cabling if needed. Maintenance and equipment past demarcation points is the customers responsibly.
Below examples shows these terms how they usually look like in reality:
Figure 1: Demarcation point marking end of PSTN and start of PBX private network.
Figure 2: Demarcation points and various devices in end users shelf