Audio codec support

G.711 a-law and mu-law, G.722, G.729a, Internet Low Bitrate Codec (iLBC), and Internet Speech Audio Codec (iSAC)

Key call features support

+ Dialing Abbreviated dialing
Adjustable ring tones and volume levels Adjustable display brightness
Agent greeting Auto-answer
Auto-detection of headset cBarge
Busy Lamp Field (BLF)
Busy Lamp Field (BLF) Pickup Busy Lamp Field (BLF) speed dial Callback
Call forward
Call forward notification Call filter
Call history lists Call park
Call pickup Call timer Call waiting
Call chaperone Caller ID Corporate directory
Conference, including traditional Join feature Cross Cluster ExtensionMobility (EMCC) Direct transfer
Extension mobility Fast-dial service
Forced access codes and client matter codes Group call pickup
Hold Intercom
Immediate divert Malicious-caller ID
Message-waiting indicator (MWI) Meet-me conference
Mobility
Music on hold (MoH) Mute
Network profiles (automatic)
On- and off-network distinctive ringing Personal directory
PickUp
Predialing before sending Privacy
Private Line Automated Ringdown (PLAR) Redial
Ring tone per line appearance
Service Uniform Resource Locator (URL) Shared line
Silent monitoring and recording Speed dial
Time and date display Transfer
Uniform Resource Identifier (URI) dialing Visual voice mail
Voice mail Whisper coaching

Electronic hookswitch

You 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 Proximity

Audio 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) options

The 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 features

Session Initiation Protocol (SIP) for signaling Session Description Protocol (SDP)
IPv4 and IPv6
User Datagram Protocol (UDP) (used only for Real-Time Transport Protocol [RTP] streams) Dynamic Host Configuration Protocol (DHCP) client or static configuration
Gratuitous Address Resolution Protocol (GARP) Domain Name System (DNS)
Trivial File Transfer Protocol (TFTP)
Secure Hypertext Transfer Protocol (HTTPS) VLAN
Real-Time Transport Protocol (RTP) Real-Time Control Protocol (RTCP)
Cisco Peer-to-Peer Distribution Protocol (PPDP) Cisco Discovery Protocol
LLDP (including LLDP-MED) Switch speed auto-negotiation

Security features

Secure boot
Secure credential storage Device authentication
Configuration file authentication and encryption Image authentication
Random bit generation
Hardware cryptographic acceleration Certificate 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 TLS Media authentication and encryption using SRTP HTTPS for client and server
Secure Shell (SSH) Protocol server
Secure 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 composition

Polycarbonate acrylonitrile butadiene styrene (ABS) textured plastic; Cosmetic class A

Operational temperature

32 to 104°F (0 to 40°C)

Nonoperational temperature shock

14 to 140°F (-10 to 60°C)

Humidity

Operating 10 to 90%, noncondensing
Non-operating 10 to 95%, noncondensing

Language support

Arabic (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 compliance

Regulatory compliance
◦ CE Markings per directives 2004/108/EC and 2006/95/EC
Safety
◦ 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
◦ GB4943
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
◦ EN61000-3-2
◦ EN61000-3-3
◦ KN22 Class B
EMC - Immunity
◦ EN55024
◦ CISPR24
◦ EN60601-1-2
◦ KN24
◦ Armadillo Light
Telecom
◦ FCC Part 68 HAC
◦ CS-03-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)
Radio
◦ FCC Part 2.1093 (BT RF Exposure TR)
◦ RSS-102 (BT RF Exposure TR)
◦ RSS-210
◦ 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