Cisco IP Phone & Accessories Cisco CP-8851-K9

Key Features:

Display: 5-inch high-resolution color display (800 x 480 pixels)
Audio: Wideband audio for superior voice clarity
Connectivity:
- Gigabit Ethernet ports (2)
- PoE (Power over Ethernet) support
USB: USB port for wired or wireless headsets
Wi-Fi: Not available by default (for Wi-Fi support, you’d need a different SKU or a separate module)
Bluetooth: Supported (for headsets and mobile phone integration)
Lines: Supports up to 5 programmable lines
Security: Secure boot, signed images, cryptographic hardware acceleration

Description
Reviews (0)

Cisco CP-8851-K9 IP Phone

Cisco CP-8851-K9 integrates 5 inches high-resolution widescreen VGA backlit color display. It supports Localized language to meet the needs of global users.
Bluetooth 3.0 supports phone book object exchange between devices, two USB ports enhance the usability of call handling by enabling wired or wireless headsets, as well as provide charging capability to mobile devices such as smartphones or tablets. The five programmable line keys support multiple directory numbers or calling features.

Key Features

Lines & Programmable Keys: 5 programmable line keys for multiple directory numbers or features; soft keys; fixed function keys for transfer / hold / conference etc. Can handle multiple calls per line.
Display: 5-inch high-resolution color display (800 x 480 pixels)
Audio Quality: Wideband audio support (e.g. codec G.722) across handset, headset, and speakerphone and Full‑duplex speakerphone.
Network & Connectivity: Dual Ethernet ports: includes an integrated switch to connect both the phone and a PC via the phone. Ethernet speed: 10/100 Mbps.
Power / Energy Efficiency: Supports Power over Ethernet (PoE) — IEEE 802.3af, PoE support (class 3 or class 4 depending on hardware revision) to simplify power. Some models support external power if PoE not available.
Fixed Function/Usability Features: Dedicated buttons for features like conference, directory, messaging, navigation. Replaceable bezel (frame) options (e.g. silver or black) to match decor. Two‑position footstand; also wall‑mountable.
Common Calling & Telephony Features: Supports standard telephony features: call forward, call pickup, call park, transfer, hold/resume, voicemail, mute, speed‑dial, caller ID, redial, etc. Advanced features: Busy Lamp Field (BLF), auto‑answer, headset auto‑detect, “agent greeting,” etc.
Security / Protocols: SIP signalling protocol support for secure signalling (TLS), media encryption (SRTP) in many deployments.
Environmental / Physical: Operating temperature roughly 0‑40 °C. Size and weight: 229.1 mm × 257.34 mm × 40 mm (without stand); about 1.19 kg (2.62 lbs) with handset
Simple, cost-effective administration: Flexible deployment options help you cut costs and maximize your investment. Remote workers get single sign-on access with Cisco Expressway. Latest encryption secures communications. Cisco EnergyWise helps reduce costs in off-work hours

Cisco IP Phone 7821, 7841, and 7861 User Guide for Cisco Unified Communications Manager 10.0 (SIP)

1 – Handset light strip	2 – Phone screen	3 – Softkey buttons	4-Programmable feature buttons
5 – Navigation and Select button	6 – Hold/Resume button	7- Conference button	8 – Transfer button
9 – Speakerphone button	10 – Headset button	11 – Mute button	12 – Keypad
13 – Volume button	14 – Contacts button	15 – Applications button	16 – Messages button
17- Handset

Advantages

High-Quality Audio: Supports wideband audio for clearer voice calls.
Security: “K9” in Cisco gear usually means it includes enhanced encryption/security features — for phones, this means secure signaling and media encryption.
Rich Features: Supports Cisco Unified Communications Manager, plus advanced telephony features like conferencing, corporate directory access, and XML apps.
Large Display: Color display with touch-sensitive keys, improving usability.
Power over Ethernet (PoE): Simplifies deployment by powering the phone over the network cable.
Compatibility: Works well within Cisco’s Unified Communications infrastructure.
Multi-Line Support: Can handle multiple lines and calls simultaneously.
Expandability: Supports expansion modules for additional line appearances.

Limitations / Considerations

Feature Set: The “K9” usually means it includes strong encryption (e.g., VPN, IPsec, SSL) features.
Platform-specific: Some IOS images only support certain router/switch hardware platforms.
Memory and Flash Size: Limited by the hardware on the device.
Version Support: Older IOS images may not support the latest protocols or security standards.
Licensing: Some features might require additional licenses to be enabled.