Cisco 7800 Series Administration Guide

Network port (10/100 SW) connection.
IEEE 802.3af power enabled.
4DC adapter port (DC48V).1
Access port (10/100 PC) connection
(optional).
5AC-to-DC power supply (optional).2
Handset connection.6AC power wall plug (optional).3
Cisco IP Phone 7821
Phone Connections
Connect your Cisco IP phone to your LAN with an Ethernet cable to enable full functionality of your Cisco
IP phone. If your Ethernet port is equipped with Power over Ethernet (PoE), you can power the Cisco IP
phone through the LAN port. Do not extend the LAN Ethernet cable outside the building. For your phone to
work, it must be connected to the IP telephony network.
Cisco IP Phone 7800 Series Multiplatform Phones Administration Guide
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About the Cisco IP Phone
Cisco IP Phone 7821

Cisco 7800 Series Specifications

General

Wireless	No
Video Support	No
PoE	Yes, 802.3af/at
Audio Codec Support	G.711, G.722, G.729, iLBC
Network Protocols	SIP, SDP, IPv4, IPv6, UDP, TCP, DNS, TFTP, HTTP, HTTPS, DHCP
Security Features	802.1X, TLS, SRTP
Power Options	PoE
Headset Port	3.5mm
Buttons	Line keys, navigation cluster, softkeys, mute, speakerphone, headset, volume control
Bluetooth	No
Ethernet Switch	Yes, 2-port 10/100/1000
USB Port	Yes, for headset (7875)