Visual message display (handset): This illuminated strip is visible from all angles. Your phone also provides an audible indicator for waiting messages
Visual notification of the phone status:
"Mute" button: When the microphone is muted, the button lights up.
Loudspeaker button: When the loudspeaker is activated, the button lights up.
Support for inline amplifiers (handsets): Cisco IP Phone handsets support third-party inline amplifiers. Connect an amplifier to the cable between the handset and the phone
Adjustable ringtone, pitch and volume
Hearing Aid Compatible (HAC) handset: Hearing aid compatibility, Magnetic coupling of the hearing aid, Federal Communications Commission (FCC) volume regulations for the Americans with Disabilities Act (ADA), Section 508 volume requirements are met through the use of industry standard inline receiver amplifiers
The CP-8851 has a Bluetooth interface that can be used to pair a hearing aid or headset
Support for headsets/hearing aids (Bluetooth, USB, analog)
Visual signaling of incoming calls, calls on hold, etc.
High-contrast visual and audible notification of an incoming call: Informs you of an incoming call. The handset light bar flashes for incoming calls and lights up when a voicemail message is received.
Line and function buttons on the left side of the screen:
Green illuminated: Active call or bidirectional intercom call
Flashing green: call on hold
Illuminated yellow: idle function active or logged in to hunt group
Flashing yellow: Incoming call or call on hold
Lit red: Line is being used on another device
Illuminated LCD screen with adjustable contrast on the Cisco IP phone
Standard layout with 12 buttons with marking on button 5
Button groupings:
Loudspeaker, headset, mute microphone
Hold, consultation/connect, conference
Voicemail, settings, phone book
Volume rocker
Adjustable font size (CP-8851 only)
Voice feedback (CP-8851 only)
Keyboard navigation and shortcuts https://help.webex.com/en-us/article/7wr87q/Webex-App-%7C-Keyboard-navigation-and-shortcuts
Support of screen readers (JAWS screen reader version 18 or higher), under MAC-OS support of the integrated screen reader
Dark mode
Adjustable font size
High contrast: If you set a high contrast for your operating system, the Webex app adopts this setting and displays the high-contrast color palette you have selected.
large buttons
Hands-free system
Standard layout with 12 buttons with marking on button 5
Wall mounting possible (wall bracket for CP-7841)
Clients available for PC/notebook and smartphone
Unterstützung Fernsteuerung (Rufannahme/Auflegen, Lautstärke, Mikro stumm) bei ausgewählten Headsets
https://www.cisco.com/c/en/us/products/unified-communications/uc_endpoints_accessories.html