Cisco 8851 IP Phone Manual

The Cisco 8851 is a high-performance IP phone designed for business environments, featuring a high-resolution color display, support for up to 10 lines, integrated Gigabit Ethernet switch, Power over Ethernet (PoE) support, HD voice quality, built-in Bluetooth for headset connectivity, and advanced security features. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Devices 7. Using Phone Features 8. Accessibility Features 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: High-resolution color display, Handset, Speakerphone, Line keys, Navigation cluster, Volume buttons, Headset port, Ethernet ports.

Feature	Description
Display	High-resolution color LCD with adjustable backlight
Line Support	Up to 10 lines with programmable line keys
Network	Integrated Gigabit Ethernet switch with PoE support
Audio	HD voice quality, wideband audio support
Bluetooth	Built-in for wireless headset connectivity
Headset Port	3.5mm jack for wired headset connection
Speakerphone	Full-duplex speakerphone with echo cancellation
Security	802.1X authentication, encrypted signaling
Power	PoE (802.3af) or optional power adapter
Mounting	Wall mountable with included bracket

Installation

Unpack and inspect contents. Place on stable surface or mount on wall.

Connect to network: Use Ethernet cable to connect phone to network switch.
Connect handset: Plug handset cord into handset port.
Power the phone: Use PoE from switch or connect power adapter.
Optional headset: Connect wired headset to headset port or pair Bluetooth headset.

WARNING! Use only approved power sources. Ensure proper ventilation around phone.

First-Time Setup

Power on phone; follow on-screen prompts.

Network configuration: Phone will obtain IP address via DHCP automatically.
Phone registration: Enter extension number and credentials as provided by administrator.
Set language: In Settings menu, select preferred language.
Adjust settings: Configure time zone, ringtone, volume levels.
Test call: Make test call to verify audio quality and connectivity.

CAUTION! Do not place phone near heat sources or in direct sunlight.

Specifications

Display: 5-inch color LCD, 480 x 272 pixels.
Network: 10/100/1000 Mbps Ethernet with PoE (802.3af).
Audio Codecs: G.711, G.722, G.729, iLBC.
Protocols: SIP, SCCP, 802.1X, LLDP-MED.
Bluetooth: Version 3.0, HSP and HFP profiles.
Power Consumption: 4.5W typical with PoE.
Operating Temperature: 32°F to 104°F (0°C to 40°C).
Dimensions: 8.7" x 10.2" x 6.3" (220 x 260 x 160 mm).
Weight: 3.3 lbs (1.5 kg).

Controls and Settings

Access menu via Settings button. Front Panel: Line keys, Navigation cluster, Volume buttons, Mute, Headset, Speakerphone.

Buttons: Hold, Transfer, Conference, Voicemail, Settings, Directory, Applications, Volume Up/Down.

Display Settings: Brightness, contrast, backlight timeout. Audio Settings: Ringtone selection, volume levels for ringer, handset, speakerphone. Network Settings: IP configuration, VLAN settings, QoS. Phone Settings: Time/date, language, screen saver. Security: Password protection, authentication settings.

Connecting Devices

Network: Ethernet cable to switch port. Headset: Wired to headset port or Bluetooth pairing. PC: Optional PC port for daisy-chaining.

Turn off phone before connecting additional devices.
Match cables to ports (Ethernet to network port).
For Bluetooth headset: Enable Bluetooth in settings, put headset in pairing mode.

Tip: Use shielded Ethernet cables for best performance in noisy environments.

Using Phone Features

Supports basic and advanced telephony features.

Make call: Lift handset or press Speakerphone, dial number.
Answer call: Lift handset or press Answer softkey.
Hold: Press Hold button to place call on hold.
Transfer: During call, press Transfer, dial target number, press Transfer again.
Conference: During call, press Conference, dial second party, press Conference again.
Voicemail: Press Voicemail button to access messages.
Directory: Press Directory to access personal and corporate directories.
Call History: Press Applications, select Call History.
Speed Dials: Program frequently called numbers to line keys.

WARNING! Do not use phone with wet hands or in wet conditions.

Accessibility Features

Visual Alerts: Flashing LED for incoming calls. Audio Adjustments: Separate volume controls for ringer, handset, speakerphone. High Contrast: Option for high contrast display mode. Large Font: Option for larger font size on display.

Care & Cleaning

Unplug before cleaning. Use slightly damp cloth with mild detergent; dry thoroughly.

CAUTION! Do not use abrasive cleaners or solvents. Avoid liquid contact with ports.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits for commercial use. CE marked for European compliance. Copyright © 2025 Cisco Systems, Inc. All rights reserved. For support, visit www.cisco.com or contact Cisco Technical Assistance Center.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power	PoE/Power adapter	Check Ethernet cable connection; verify PoE switch is powered; try power adapter.
No network connectivity	Cable/Configuration	Check Ethernet cable; verify network settings; restart phone.
No audio	Volume/Mute	Check volume settings; ensure mute is off; test with handset and speakerphone.
Display issues	Settings/Power	Adjust brightness/contrast; restart phone; check for loose connections.
Cannot make/receive calls	Registration/Network	Verify phone is registered; check network connectivity; contact administrator.
Bluetooth not working	Pairing/Settings	Ensure Bluetooth is enabled; re-pair headset; check headset battery.

Reset: Settings > Admin Settings > Reset to restart or factory reset.

Service: Contact Cisco Technical Assistance Center or authorized service provider.