What does the ISDN R reference point define?
The R reference point defines the point between a non-ISDN-compatible device and a TA. What does the ISDN S point reference? The S point references the points or customer equipment that connects to the NT2 or customer-switching device. What does the ISDN T reference point define? ISDN T reference points refer to the point between NT1 and NT2 devices. T and S reference points are electronically the same and reference the outbound connection from the NT2 to the ISDN network. What is the ISDN U reference point? The U reference point is the point between the NT1 and the ISDN network. What happens when you connect a router with a U interface into an NT1? If you connect a router with a U interface into an NT1, you will damage the interface. This is because the U interface on a Cisco router already has a built-in NT1. What are SPIDs? Service provider or profile identifiers (SPIDs) are used to identify your router to the switch at the central office (the ISP). They are a series of characters t
