Cisco UC Phone CP-8851 Manual

The Cisco Unified Communications Manager (Unified CM) IP Phone 8851 is a full-featured, high-quality business phone designed for managers and executives. It features a high-resolution color display, support for up to 10 lines, integrated Gigabit Ethernet switch, built-in Bluetooth for headset connectivity, HD voice, and a wideband-capable handset and speakerphone. 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, Softkeys, Bluetooth module, Gigabit Ethernet ports.

Feature	Description
Display	5-inch (480 x 272 pixels) grayscale or color LCD with backlight
Network Ports	Dual Gigabit Ethernet (10/100/1000 Mbps) with integrated switch
Bluetooth	Integrated for wireless headset connectivity
Audio	HD wideband audio on handset and speakerphone
Line/Feature Keys	Up to 10 line or feature keys with multi-color LEDs
Power Options	Power over Ethernet (PoE) 802.3af or external power adapter
Headset Port	Dedicated headset port (optional headset required)
Navigation Cluster	5-way navigation button for menu control
Volume Rocker	Controls handset, headset, speakerphone, and ringer volume
Security	802.1X authentication, encrypted signaling/media

Installation

Unpack and inspect contents. Place on stable surface.

Connect to Network: Use Ethernet cable to connect the SW port to your network switch. Use PC port to connect a computer.
Connect Handset: Plug the handset cord into the HANDSET port.
Power the Phone: Use Power over Ethernet (PoE) from your switch or connect the external power adapter to the DC 48V port.
Optional Headset: Plug a wired headset into the HEADSET port or pair a Bluetooth headset.

WARNING! Use only approved power adapters. Ensure network cables are securely connected.

First-Time Setup

Power on phone; it will register with Cisco Unified Communications Manager.

Initial Boot: Phone downloads configuration from Unified CM. This may take a few minutes.
Check Registration: Look for your extension number and username on the screen.
Set Preferences: Press the Settings button to adjust ringtone, display contrast, language, etc.
Configure Voicemail: Press the Messages button to set up voicemail following prompts.

CAUTION! Do not unplug the phone during firmware download or configuration.

Specifications

Model: Cisco Unified IP Phone 8851.
Display: 5-inch grayscale or color LCD, 480 x 272 pixels.
Network: Dual 10/100/1000 Mbps Ethernet with PoE (802.3af Class 3).
Protocols: SIP (Session Initiation Protocol) and SCCP (Skinny Client Control Protocol).
Audio Codecs: G.711, G.722, G.729a, iLBC, Opus.
Bluetooth:Version 3.0+ for headset profile (HFP 1.6).
Power Consumption: 5.0W (typical), 6.3W (max with accessories).

Operating Temp: 32°F to 104°F (0°C to 40°C).

Supported Services: Voicemail, call forwarding, conferencing, hold, transfer.

Controls and Settings

Access menus via the Settings button or navigation cluster.

Front Panel: Line keys, Speakerphone, Mute, Headset, Volume rocker, Navigation cluster, Softkeys.

Common Settings: Ringtone selection, Display contrast/brightness, Time/Date format, Network configuration (usually automatic), Bluetooth pairing, Audio settings (handset, headset, speakerphone levels).

Call Features: Hold, Transfer, Conference, Forward All, Do Not Disturb, Park, Pickup.

Connecting Devices

Network: SW port to switch, PC port to computer. Handset: Standard RJ-9 connector. Headset: Wired to HEADSET port or Bluetooth.

Turn off or unplug devices before connecting cables if possible.

Match cables to correct ports (Ethernet, handset, headset).

For Bluetooth: Go to Settings > Bluetooth > Add Device to pair.

Tip: Use quality Category 5e or higher Ethernet cables for Gigabit performance.

Using Phone Features

Supports basic and advanced telephony features.

Make a Call: Lift handset or press Speakerphone, dial number, or press a line key.

Answer a Call: Lift handset, press Speakerphone, or press the flashing line key.

Hold: Press Hold button; resume by pressing the held line key.

Transfer: During a call, press Transfer, dial the target number, press Transfer again.

Conference: During a call, press Conference, dial the second party, press Conference again to merge.

Voicemail: Press Messages button and follow prompts.

Call History: Press the Applications button and select Recent Calls.

Speed Dials: Assign numbers to line/feature keys via the phone web interface or Unified CM.

WARNING! Do not use excessive force on buttons or navigation cluster.

Accessibility Features

Hearing Aid Compatibility (HAC): Handset is HAC rated. Visual Alerts: Flashing line key LEDs for incoming calls. Audio Adjustments: Independent volume controls for ringer, handset, headset, and speakerphone. High-Contrast Display: Adjustable in settings.

Care & Cleaning

Unplug power and network cables before cleaning. Use a soft, dry, lint-free cloth. For stubborn marks, dampen cloth slightly with water. Do not use liquids, aerosols, or abrasive cleaners.

CAUTION! Never spray cleaner directly on the phone. Keep liquids away from all openings.

Regulatory Information

FCC Part 15: Class A digital device; complies with limits for business use. ICES-003: Complies with Canadian EMI regulations. CE Marked: Conforms to European EMC and safety directives. RCM: Complies with Australian communications standards. For support, visit www.cisco.com/go/support or contact your system administrator. Copyright © 2015-2025 Cisco Systems, Inc. All rights reserved.

Troubleshooting

Symptom Possible Cause Corrective Action

Phone not powering on Power source Check PoE switch or power adapter connection; try a different outlet.

No display or blank screen Power/backlight Check power; adjust display brightness in Settings.

No network registration Network cable/config Ensure Ethernet cable is secure; phone should get IP via DHCP; contact admin.

No dial tone Line configuration Check with system administrator; ensure phone is registered to Unified CM.

Poor audio quality Network/connections Check handset cord; test with speakerphone; network may have packet loss.

Bluetooth not pairing Distance/pairing mode Ensure headset is in pairing mode and within 3 feet; restart phone Bluetooth.

Reset: To restart, unplug power and reconnect. For factory reset (erases all settings), press and hold # while plugging in power, release when light flashes.

Service: Contact your Cisco system administrator or visit www.cisco.com/go/support.

Cisco UC Phone CP-8851 Manual © - All Rights Reserved 2025

Symptom	Possible Cause	Corrective Action
Phone not powering on	Power source	Check PoE switch or power adapter connection; try a different outlet.
No display or blank screen	Power/backlight	Check power; adjust display brightness in Settings.
No network registration	Network cable/config	Ensure Ethernet cable is secure; phone should get IP via DHCP; contact admin.
No dial tone	Line configuration	Check with system administrator; ensure phone is registered to Unified CM.
Poor audio quality	Network/connections	Check handset cord; test with speakerphone; network may have packet loss.
Bluetooth not pairing	Distance/pairing mode	Ensure headset is in pairing mode and within 3 feet; restart phone Bluetooth.