The Cisco 2600XM/2691/3700 Series IP Communications High-Density Digital Voice/Fax Network Module is part of the Cisco Systems® IP Communications suite of solutions. One of three options for high-density digital voice, WAN, and analog voice connectivity and conferencing and transcoding capabilities in a single network module, the NM-HDV2 supports a VIC/VWIC slot that can fitted with either digital or analog/BRI voice/WAN interface cards. It supports to 60 channels of digital voice or four channels of analog voice in a medium complexity codec. For flexibility, the IP Communications High-Density Digital Voice/Fax Network Module operates with the Cisco CallManager system with Survivable Remote Site Telephony (SRST) and Cisco CallManager Express.