Cisco 7821 Administration Guide

CHAPTER 13
Troubleshooting
• General Troubleshooting Information, on page 305
• Startup Problems, on page 307
• Phone Reset Problems, on page 309
• Phone Cannot Connect to LAN, on page 310
• Audio Problems, on page 311
• General Telephone Call Problems, on page 311
• Feature Troubleshooting, on page 312
• Phone Display Problems, on page 314
• Report All Phone Issues from the Phone Web Page, on page 316
• Report a Phone Problem Remotely, on page 317
• Troubleshooting Procedures, on page 317
• Additional Troubleshooting Information, on page 318
General Troubleshooting Information
The following table provides general troubleshooting information for the Cisco IP Phone.
Table 23: Cisco IP Phone Troubleshooting
ExplanationSummary
Cisco does not support connecting an IP phone to
another IP Phone through the PC port. Each IP Phone
should connect directly to a switch port. If phones are
connected together in a line by using the PC port, the
phones do not work.
Connecting a Cisco IP Phone to another Cisco IP
Phone
A prolonged Layer 2 broadcast storm (lasting several
minutes) on the voice VLAN may cause IP phones to
reset, lose an active call, or be unable to initiate or
answer a call. Phones may not come up until a
broadcast storm ends.
Prolonged broadcast storms cause IP phones to reset,
or be unable to make or answer a call
Cisco IP Phone 7800 Series Multiplatform Phones Administration Guide
305

Cisco 7821 Specifications

General

Brand	Cisco
Model	7821
Category	IP Phone
Language	English