The Cisco® Fourth-Generation 1-, 2-, 4-, and 8-Port T1/E1 Multiflex Trunk Voice and WAN Network Interface Modules (NIMs) support data and voice applications on the Cisco 4000 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 superior flexibility, versatility, and investment protection through their many uses. Customers who choose to integrate data and voice in multiple steps preserve their investment in a T1/E1 WAN interface.
The fourth-generation Cisco T1/E1 NIMs add improvements over the Cisco Second- and Third-Generation T1/E1 Multiflex Trunk Voice and WAN Interface Cards (MFT VWIC2s and VWIC3s, respectively). The fourth-generation T1/E1 modules enable each port to be clocked from an independent clock source for data applications. Voice applications can now be clocked independently from data applications, with all ports for voice applications clocked from a single source.