CISCO 6851 + Ext. Board

Affordable IP phones for VoIP

The Cisco 6851 offers a budget-friendly, easy to use IP desk phone with multiplatform support for third-party hosted deployments. Featuring an attractive ergonomic design and Gigabit Ethernet connection as standard, the 6851 offers a reliable, secure device with a range of features including programmable line keys, tri-colour LEDs for waiting/incoming call indication and a 3.5″ greyscale display with white backlighting for easy reading.

Key Features

  • Four programmable line/feature keys and Four programmable soft keys.
  • Message waiting/incoming call indicator LED on handset.
  • Hearing aid compatible (HAC) handset.
  • Hands-free talking (speakerphone).
  • 4 SIP accounts.
  • 2x 10/100/1000 Gigabit Ethernet Ports and 1 RJ9 port.

View datasheet in PDF format

Cisco Voip Phone 6851 ext board

Phone overview

The 6851 Phone combines an attractive new ergonomic design with “always-on” reliability and secure encrypted communications. The phone delivers advanced IP telephony features and wideband audio capabilities with an easy-to-use, full-featured voice communications experience on third-party hosted call control.The line keys on each model are fully programmable.

Extension Board

The Cisco IP Phone 6800 Key Expansion Module (KEM) extends the capabilities of the Cisco IP Phone 6851 with additional buttons. This module adds 14 physical buttons along with access to 14 additional buttons via the page buttons, for a total of 28 additional buttons. The KEM supports the Programmable Line Key (PLK) function, but does not support any SIP registrations. Calls may be monitored and answered using the PLK function, but calls may not initiated from the KEM. The 6851 IP phone supports one KEM only.

Hardware features

Features Benefits

Ergonomic design

●  An easy-to-use interface that provides a traditional telephony-like user experience.

Graphical display

●   White backlit, grayscale, 3.5-in. (9-cm) 396 x 162-pixel display.
●  Scrollable access to calling features and text-based XML applications.


●  Supports either a narrowband or a wideband audio handset connected through an RJ-9 port.
●  he 6800 series handsets produce a magnetic field that attracts small metallic objects such as pins and staples. To avoid possible injuries, do not keep small metallic objects close to the handset.
●  The handset is hearing aid-compatible (HAC) and meets Federal Communications Commission (FCC) loudness requirements for the Americans with Disabilities Act (ADA). You can achieve Section 508 loudness requirements by using industry-standard inline handset amplifiers such as Walker Equipment W-10 or CE-100 amplifiers. The dial pad is also ADA-compliant.


●  The analog headset jack is a standard wideband-capable RJ-9 audio port for the IP Phone 6821.

Backlit Indicator

●  Backlit indicators on the audio path buttons (handset, headset, and speakerphone), select, line, and message waiting buttons.

Volume control

●  A volume-control toggle provides easy decibel-level adjustments of the handset, monitor speaker, and ringer.

Full duplex speakerphone

●  A full-duplex speakerphone gives you flexibility in placing and receiving calls. For added security, the Audible Dual-Tone Multi-frequency (DTMF) tones are masked when the speakerphone mode is used.


●  The IP Phone 7861 includes a default black bezel (replaceable), and an optional silver bezel is also available separately.

Single-position foot stand

●  The foot stand holds the phone in a single position, making the display easy to view and the buttons easy to use while sitting down. You can remove the foot stand for wall mounting. There are mounting holes located on the back of the phone.


●  Can be wall-mounted using the optional 6800 Series wall-mount kit (available separately).


The phone has the following keys:
●   Line keys
●   Soft-keys
●   Service
●   Speakerphone, headset, and mute
●   Two-way navigation and select keys
●   Hold/Resume, Transfer and Conference keys
●   Messaging, Service and Directory keys
●   Standard keypads
●   Volume control toggle key

Ethernet cables

●   Category 3/5/5e/6 for 10-Mbps cables with 4 pairs
●   Category 5/5e/6 for 100-Mbps cables with 4 pairs

Electronic hook switch

●  6851 only: Electronic hookswitch headset support via its auxiliary port.

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