The Fourth-Generation 1- 2- 4- and 8-PortT1/E1Multiflex Trunk Voice and WAN Network Interface Modules (NIMs) support data and voice applications on the 4451-X Integrated Services Routers (Figure 1). These cards combine WAN-interface-card (WIC) voice-interface-card (VIC) ISDN Primary Rate Interface (PRI) dial-access integration and channelized-data (CE1T1) functions to provide unparalleled flexibility versatility and investment protection through their many uses.