The Cisco 1-port T1 Multi-Flex Voice/WAN Interface Cards (Multi-Flex VWICs) support voice and data applications on a variety of Cisco multiservice platforms. This list of platforms includes the Cisco 1700, 2600, 2600XM, 2691, 2800, 3600, and 3700 multiservice routers, as well as the Cisco VG200, WS-X4604-GWY, C4224, and ICS 7750 voice gateways
The 1-port T1 Multi-Flex Trunk VWICs are not like the T1 channel service unit/data service unit (CSU/DSU) (WIC-1DSU-T1). The T1 Multi-Flex Trunk VWICs can transmit either voice and data or both based on the network module they are installed in and whether Digital Signal Processors (DSPs) exist on the module.
This Multi-Flex Trunk can be used as a Voice Interface Card when combined with appropriate accompanying hardware (such as an NM-HDV, NM-HDV2, an NM-HD-2VE, or an AIM-VOICE-30 and AIM-ATM-VOICE-30 card), or as a WIC (in a WIC slot in the 2600, 2800 or 3600). Therefore, it is a Voice WAN Interface Card (VWIC).
The Multi-Flex Trunk provides physical layer T1 access. The capabilities of that T1 interface are determined by the host it is plugged into.
This Multi-Flex Trunk card does not support ISDN data or modem termination in a traditional Network Access Server (NAS) dial scenario. Under specific scenarios, ISDN data and modem connectivity can be possible when the VWIC is used for packet voice, such as in the case of Modem Pass-through and Modem Relay to a peer voice gateway. Such features are beyond the scope of this document.
For more information, visit Cisco’s web site at: http://www.cisco.com/c/en/us/support/docs/routers/3600-series-multiservice-platforms/8106-vwicmf-t1.html