VoIP phone SIP RTCP RTP SRTP SDP 5 lines Power Adapter Sold Separately

Additional information




Cisco CP-8851-K9 IP Phone Overview



The Cisco IP Phone 8851 is a business-class collaboration endpoint that combines high-fidelity, reliable, secure, and scalable voice communications with Cisco Intelligent Proximity for telephony integration for personal mobile devices to support midsize to large enterprise businesses. With the Cisco IP Phone 8851, you can increase personal productivity through an engaging user experience that is both powerful and easy-to-use. The IP Phone 8851 combines an attractive ergonomic design with wideband audio for crystal clear voice communications, "always-on" reliability, encrypted voice communications to enhance security, and access to a comprehensive suite of unified communication features from Cisco communication servers. In addition, Cisco Intelligent Proximity brings the worlds of desk and mobile together for you when you are using your mobile device at the desk for your work. You can move the audio path over to the Cisco IP Phone 8851 during active mobile calls to take advantage of its superior audio acoustics. An example would be to share a conversation with a colleague who you want to listen in. This capability gives you greater flexibility and superior user experience when at your desk. The IP Phone 8851 also comes standard with a USB port so you can charge your smartphone when at your desk, and stay connected when away from your desk. The Cisco IP Phone 8851 offers five programmable line keys. You can configure keys to support either multiple directory numbers or calling features such as speed dial. You can also boost productivity by handling multiple calls for each directory number using the multicall-per-line feature. Fixed-function keys give you one-touch access to applications, messaging, directory, as well as often-used calling features such as hold/resume, transfer, and conference. A five-way navigation cluster helps you transition through menus more easily. Backlit acoustic keys provide flexibility for audio path selection and switching.


Display5" high-resolution (800 x 480) WVGA color display
Ethernet Switch10/100/1000
Programmable Line Keys4
Number of Line Keys5
Full Duplex SpeakerphoneYes
Wideband AudioYes
PoE ClassificationClass 3
Bluetooth / DECTBluetooth
USB (Physical Ports)2 Ports
KEM (Key Expansion Module)Two Optional KEM
Third-party Call ControlYes
Replaceable BezelYes (Black, Silver)
Wall MountableYes
Audio codec supportG.711 a-law and mu-law, G.722, G.729a, Internet Low Bitrate Codec (iLBC), and Internet Speech Audio Codec (iSAC)
Key call features supportDialingAbbreviated dialingAdjustable ring tones and volume levelsAdjustable display brightnessAgent greetingAuto-answerAuto-detection of headsetcBargeBusy Lamp Field (BLF)Busy Lamp Field (BLF) PickupBusy Lamp Field (BLF) speed dialCallbackCall forwardCall forward notificationCall filterCall history listsCall parkCall pickupCall timerCall waitingCall chaperoneCaller IDCorporate directoryConference, including traditional Join featureCross Cluster Extension Mobility (EMCC)Direct transferExtension mobilityFast-dial serviceForced access codes and client matter codesGroup call pickupHoldIntercomImmediate divertMalicious-caller IDMessage-waiting indicator (MWI)Meet-me conferenceMobilityMusic on hold (MoH)MuteNetwork profiles (automatic)On- and off-network distinctive ringingPersonal directoryPickUpPredialing before sendingPrivacyPrivate Line Automated Ringdown (PLAR)RedialRing tone per line appearanceService Uniform Resource Locator (URL)Shared lineSilent monitoring and recordingSpeed dialTime and date displayTransferUniform Resource Identifier (URI) dialingVisual voice mailVoice mailWhisper coaching
Electronic hookswitchYou can control the hookswitch electronically with a third-party headset connected to either the USB port or auxiliary port, or directly paired with the phone through bluetooth.
Cisco Intelligent ProximityAudio path moving sends audio through the IP Phone 8851 for a mobile device-connected call.Call history synchronization allows you to view placed and missed calls of your mobile device from the
IP Phone 8851.Contact synchronization allows you to synchronize the contact objects from your mobile device to your
IP Phone 8851.
Quality-of-service (QoS) optionsThe phone supports Cisco Discovery Protocol and 802.1Q/p standards, and can be configured with an 801.1Q VLAN header containing the VLAN ID overrides configured by the Admin VLAN ID.
Network featuresSession Initiation Protocol (SIP) for signalingSession Description Protocol (SDP)IPv4 and IPv6User Datagram Protocol (UDP) (used only for Real-Time Transport Protocol [RTP] streams)Dynamic Host Configuration Protocol (DHCP) client or static configurationGratuitous Address Resolution Protocol (GARP)Domain Name System (DNS)Trivial File Transfer Protocol (TFTP)Secure Hypertext Transfer Protocol (HTTPS)VLANReal-Time Transport Protocol (RTP)Real-Time Control Protocol (RTCP)Cisco Peer-to-Peer Distribution Protocol (PPDP)Cisco Discovery ProtocolLLDP (including LLDP-MED)Switch speed auto-negotiation
Security featuresSecure bootSecure credential storageDevice authenticationConfiguration file authentication and encryptionImage authenticationRandom bit generationHardware cryptographic accelerationCertificate Authority Proxy Function (CAPF)Manufacturer-Installed Certificates (MIC)Locally Significant Certificates (LSC)Ethernet 802.1x supplicant options: Extensible Authentication Protocol-Flexible Authentication via Secure Tunneling (EAP-FAST) and Extensible Authentication Protocol-Transport Layer Security (EAP-TLS)Signaling authentication and encryption using TLSMedia authentication and encryption using SRTPHTTPS for client and serverSecure Shell (SSH) Protocol serverSecure Sockets Later (SSL)-based VPN client
Physical dimensions
(H  W  D)
9.02 x 10.13 x 1.57 in. (229.1 x 257.34 x 40 mm) (excluding foot stand)
Weight (with handset)2.62 lb (1.19 kg)
Phone-casing compositionPolycarbonate acrylonitrile butadiene styrene (ABS) textured plastic; Cosmetic class A
Operational temperature32 to 104F (0 to 40C)
Nonoperational temperature shock14 to 140F (-10 to 60C)
Operating 10 to 90%, noncondensingNon-operating 10 to 95%, noncondensing
Language supportArabic (Arabic Area)Bulgarian (Bulgaria)Catalan (Spain)Chinese (China)Chinese (Hong Kong)Chinese (Taiwan)Croatian (Croatia)Czech (Czech Republic)Danish (Denmark)Dutch (Netherlands)English (United Kingdom)Estonian (Estonia)French (France)French (Canada)Finnish (Finland)German (Germany)Greek (Greece)Hebrew (Israel)Hungarian (Hungary)Italian (Italy)Japanese (Japan)Latvian (Latvia)Lithuanian (Lithuania)Korean (Korea Republic)Norwegian (Norway)Polish (Poland)Portuguese (Portugal)Portuguese (Brazil)Romanian (Romania)Russian (Russian Federation)Spanish (Columbia)Spanish (Spain)Slovak (Slovakia)Swedish (Sweden)Serbian (Republic of Serbia)Serbian (Republic of Montenegro)Slovenian (Slovenia)Thai (Thailand)Turkish (Turkey)
Certification and complianceRegulatory compliance
   CE Markings per directives 2004/108/EC and 2006/95/EC

   UL 60950 Second Edition

   CAN/CSA-C22.2 No. 60950 Second Edition

   EN 60950 Second Edition (including A11 & A12)

   IEC 60950 Second Edition (including A11 & A12)

   AS/NZS 60950


EMC – Emissions
   47CFR Part 15 (CFR 47) Class B

   AS/NZS CISPR22 Class B

   CISPR22: 2005 w/Amendment 1: 2005 Class B

   EN55022: 2006 w/Amendment 1: 2007 Class B

   ICES003 Class B

   VCCI Class B



   KN22 Class B

EMC – Immunity




   Armadillo Light

   FCC Part 68 HAC


   AS/ACIF S004

   AS/ACIF S040

   NZ PTC 220

   Industry Standards: TIA 810 and TIA 920

   Industry Standards: IEEE 802.3 Ethernet, IEEE 802.3af and 802.3at

   Korea (RRA Public Notification 2010-36, Nov 01, 2010)

   Korea (RRA Announce 2011-2, Feb 28, 2011)

   FCC Part 2.1093 (BT RF Exposure TR)

   RSS-102 (BT RF Exposure TR)


   EN 300.328

   EN50385 (BT RF Exposure TR)

   EN 301-489-1

   EN 301-489-17

   NCC LP0002

   Korea (RRL No. 2006-128, RRL No. 2006-129)

   Japan Bluetooth GFSK/EDR        




VodaCare Services

Frustrated with expensive OEM service contracts with difficult to reach support? VodaCare can help you save 30-60% off your extended hardware service contracts with even better support than the OEM! We’ll get you connected to a certified level 4 and above engineer in as little as 10 minutes. We also offer next day hardware replacements so your system can remain online with minimal interruptions. Ask your representative about VodaCare to learn more.

Need Help?

We’ll immediately connect you to a professional to assist you.