What Does Network Termination Unit (NTU) Mean?

A network termination unit (NTU) is a device that links the customer-premises equipment (CPE) to the public switched telephone network (PSTN). The device serves as the last point of connection between the two. Typically, the service provider is the owner of the NTU, which usually supports various communication standards, including protocols and voltages, to allow different device types to communicate with the PSTN.

Techopedia Explains Network Termination Unit (NTU)

An NTU connects ISDN-based CPE to ISDN lines. It allows the CPE to be linked to the switching device at the central office (CO).