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Cisco® 4400 Series Integrated Services Router Network Interface Modules (ISRNIMs) provide highly reliable synchronous serial WAN connections for remote sites. These interfaces use well-known point-to-point WAN protocols such as High-Level Data Link Control (HDLC) and Point-to-Point Protocol (PPP) as well as Frame Relay, offering cost-effective virtualized WAN connections in both point-to-point and point-to-multipoint designs. You can mix and match NIMs to tailor cost-effective solutions for common networking solutions for low- and high-density WAN aggregation

Note:    These NIMs are not supported with Cisco 2900 and 3900 Integrated Services Routers.