A network interface device often serves as the demarcation point.
In telephony, the demarcation point is when the public switched telephone network ends and connects with the customer's on-premises wiring. The dividing line determines who is responsible for the installation and maintenance of wiring and equipment customer/subscriber or telephone company/service provider. The demarcation point varies between countries and has changed over time.
Abbreviations for The demarcation point are demarc, DMARC. The term MPOE (the minimum or central point of entry) is synonymous, with the added implication that it occurs as soon as possible upon entering the customer premises.