Cisco 7800 Series Administration Manual page 183

Troubleshooting
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General Troubleshooting Information
The following table provides general troubleshooting information for the Cisco IP Phone.
Table 12: Cisco IP Phone Troubleshooting
Summary
Connecting a Cisco IP Phone to
another Cisco IP Phone
Prolonged broadcast storms cause IP
phones to reset, or be unable to make
or answer a call
General Troubleshooting Information, page 169
Startup Problems, page 171
Cisco IP Phone Reset Problems, page 173
Phone Cannot Connect to LAN, page 174
Audio Problems, page 175
General Telephone Call Problems, page 175
Troubleshooting Procedures, page 176
Additional Troubleshooting Information, page 177
C H A P T E R
Explanation
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.
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.
Cisco IP Phone 7800 Series for Third-Party Call Control Administration Guide
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