Customer-premises equipment or customer-provided equipment (CPE) is any terminal and associated equipment located at a subscriber's premises and connected with a carrier's telecommunication channel(s) at the demarcation point ("demarc"). The demarc is a point established in a building or complex to separate customer equipment from telephone company equipment. CPE generally refers to telephones, DSL modems or cable modems, or purchased set-top boxes for use with Communications Service Providers' services. Also included are key telephone systems and most private branch exchanges. Excluded from CPE are overvoltage protection equipment and pay telephones