The Cisco Unified Communications Two-port FXS enhanced and DID voice/fax interface card for the Cisco 2800 and 3800 Series voice gateway routers enable packet voice technologies, including voice over IP (VoIP) (H.323, Media Gateway Control Protocol [MGCP], and Session Initiation Protocol [SIP]), voice over Frame Relay, and voice over ATM (ATM Adaptation Layer 2 [AAL2] and AAL5). Cisco Unified Communications solutions provide the means for integrating voice and data within a single network, allowing users to take advantage of services such as IP telephony, integrated services, and toll-bypass while providing an opportunity to improve productivity.