What is interfaces and devices in ISDN(integrated services digital network)?

In Integrated Services Digital Network (ISDN), interfaces are standardized points of connection that facilitate communication between different network elements. The primary interfaces in ISDN are the Basic Rate Interface (BRI), which consists of two B channels for data and one D channel for signaling, and the Primary Rate Interface (PRI), which offers more B channels for larger data transmission. Devices in ISDN include terminal equipment like phones and computers, as well as network equipment such as ISDN switches and terminal adapters that enable these devices to connect and communicate over the digital network. Together, interfaces and devices enable the seamless transmission of voice, data, and video over ISDN.