The Cisco Desk Phone 9851 (DP-9851-K9) is a business-grade VoIP desk phone for modern offices, home offices, and hybrid work environments. Running Cisco PhoneOS, the 9851 supports Cisco Unified Communications Manager (CUCM 12.5+), Webex Calling, Cisco BroadWorks, and 3rd Party Call Control (3PCC) platforms, all configurable without changing hardware. The backlit 3.7-inch color LCD (480x240) provides clear call management. Six physical line keys with tri-color LEDs support up to 46 total programmable line keys via soft key pages. AI-based Background Noise Removal (BNR) on the outgoing side reduces distractions, while Cisco HD audio and a bass-enhancing acoustic enclosure deliver full-duplex speakerphone clarity. HAC-compliant handset supports hearing aid users. Dual Gigabit Ethernet (10/100/1000) with PC pass-through, USB-A and USB-C headset ports, and PoE 802.3af power provide flexible connectivity. USB-C also charges a connected device when using the optional AC adapter (sold separately). TPM 2.0, TLS 1.3, SRTP, Secure Boot, and Image Authentication secure every call. ENERGY STAR certified; over 74% post-consumer recycled plastic. Includes: phone, handset, cord, desk stand, Ethernet cable. Power adapter not included.