The ISDN BRI NT/TE voice interface card enables Cisco IOS software to replicate the public switched network interface to a PBX that is compatible with European Telecommunications Standards Institute (ETSI) NET3 and QSIG switch types.In the past, customers with PBXs that implement only the BRI TE interface have had to make substantial hardware and software changes on the PBX to implement the NT interface. The implementation of an NT interface on the router allows the customer to connect ISDN PBXs and key systems to a multiservice network with a minimum of configuration changes on the PBX.