Abstract: This invention relates to a network terminal apparatus in ISDN for connecting a two-wire U-interface on the switchboard side and a four-wire S-interface on the terminal side to each other. A network terminal apparatus disclosed for causing signals from the switchboard or the terminal to enable or disable the circuitries in the periphery of transmission/reception means of S- and U-interfaces, thus dispensing with use of a microprocessor and notifying the user of the status by LED display means. It comprise U-interface means connected to a switchboard for transmitting/receiving channel data 2B+D as a reference transmission rate, S-interface means connected to a terminal for transmitting/receiving channel data 2B+D, a status display for displaying activation status of the system, and electric supply means for supplying a regular and backup source, and reset means for performing a system resetting action.