What are NT1 and TA in ISDN circuit?
The Network Termination 1 or NT1 provides the physical and electrical termination of the twisted pair coming from the phone company’s central office. The NT1 also converts the 2 wire twisted pair connection into 8 wire distribution system in user premises. This provides a standard interface for ISDN terminal equipment. Any terminal equipment designed to meet the ISDN standard can plug into this interface by using a standard 8-pin RJ-45 connector. The NT1 also provides remote diagnostic capabilities to allow central office (Telephone Exchange) to perform centralized fault isolation. The Terminal Adapter or TA is the interfacing device for using ISDN lines for data. It is generally placed after the NT1 in customer premises and the data transfer equipment can be connected to ISDN channel through it. Some ISDN terminal adapters have built-in NT1 for the means of simpler and reliable installation. In case of voice transmission ISDN telephones can be directly plugged to the NT1. Some TA’s ha
