The phone offers an easy-to-use interface and provides a traditional telephony-like user experience.

White backlit, greyscale, 3.5" 396×162 pixel-based display.

The handset is a standard wideband-capable audio handset (connects through an RJ-9 port) for the IP Phone 7821, 7841 and 7861. 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.

The phone supports backlit indicators for the audio path keys (handset, headset and speakerphone), select key, line keys, and message waiting.

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

Full-duplex speakerphone allows gives you flexibility in placing and receiving calls. For added security, the audible dual tone multifrequency (DTMF) tones are masked when the speakerphone mode is used.

This IP phone includes a default black bezel (replaceable), and an optional silver bezel sold separately.

The display is easy to view and the buttons and keys are easy to use. The two-position foot stand supports viewing angles of 30 degrees and 45 degrees; you can remove the foot stand for wall mounting, with mounting holes located on the base of the phone.

The phone can be installed on a wall using optional wall-mount kit (available separately).

The hookswitch can be controlled electronically with a third party headset connected to the auxiliary port.

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

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

IEEE PoE Class 1
The phone supports IEEE 802.3af PoE (Class 1); power consumption does not exceed 3.84 watts.
Cisco Power Cube 3
This power cube is used as a standard Cisco IP Phone Power Supply for non-PoE deployments.
Cisco Power Injector
The IP Phone 7811, 7821 and 7861 are compatible with Cisco Unified IP Phone Power Injector (CP-PWR-INJ), and 7841 is compatible with Cisco Aironet Power Injector (AIR-PWRINJ5=).

Cisco Unified Communications Manager
● 8.5.1
● 8.6.2
● 9.1.2
● 10.x and later
Cisco Business Edition 6000
● 8.6.2
● 9.1.2
● 10.x and later
Cisco Hosted Collaboration Solution
● 8.6.2 and later (using supported UCM versions above) Cisco Unified Survivable Remote Site Telephony
● 8.x and later

● Dialing (E.164)
● Abbreviated dial
● Adjustable ringing and volume levels
● Adjustable display contrast
● Agent greeting
● Auto-answer
● Auto-detection of headset
● Busy Lamp Field (BLF)
● Call back
● Call forward
● Call history
● Call park
● Call Pickup
● Call timer
● Call waiting
● Caller ID
● cBarge
● Corporate directory
● Conference
● Cross Cluster Extension Mobility (EMCC)
● Dial from the list
● Direct transfer
● Do not disturb
● Extension Mobility (EM)
● Forced access codes and client matter codes
● Group call pickup
● Hold/resume
● Immediate divert
● Intercom
● Join
● Message-waiting indicator
● Meet me conference
● Mobility
● Music on hold
● Mute
● Network profiles (automatic)
● On- and off-network distinctive ringing
● Personal directory
● Privacy
● Private Line Automated Ringdown (PLAR)
● Redial
● Ring tone per line appearance
● Shared line
● Silent monitoring and recording
● Speed dial
● Time and date display
● Transfer
● Voicemail
● Whisper coaching