Cisco 7821 Administration Guide

To reduce or eliminate any adverse effects to the phones, schedule administrative network tasks during a time
when the phones are not being used or exclude the phones from testing.
Cisco IP Phone 7800 Series Multiplatform Phones Administration Guide
327
Cisco IP Phone Troubleshooting
Phone Behavior During Times of Network Congestion

Cisco 7821 Specifications

General

Resolution	396 x 162 pixels
Lines	2
Speakerphone	Yes
Display	3.5-inch (89 mm) monochrome display
Ethernet Ports	2 x 10/100 Ethernet ports
Power	IEEE PoE Class 1
Headset Port	Yes
Protocols	SIP
Audio Codecs	G.711, G.722, G.729, iLBC
Weight	0.9 kg (1.98 lb)