Demarcation is the establishment of boundaries or limits separating two areas, groups, or things. Talks were continuing about the demarcation of the border between the two countries
meeting point for communications devices of two separate entities (ex: junction where home telephone equipment connects to the wires of the telephone company)
The point at which the local operating company's responsibility for the local loop ends Beyond the demarcation point (also known as the network interface), the customer is responsible for installing and maintaining all equipment and wiring