Cisco 7800 Series Administrator's Guide

CHAPTER 14
Troubleshooting
•
General Troubleshooting Information, page 205
•
Startup Problems, page 207
•
Phone Reset Problems, page 209
•
Phone Cannot Connect to LAN, page 210
•
Audio Problems, page 211
•
General Telephone Call Problems, page 211
•
Troubleshooting Procedures, page 212
•
Additional Troubleshooting Information, page 213
General Troubleshooting Information
The following table provides general troubleshooting information for the Cisco IP Phone.
Table 28: 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 Administration Guide for Cisco Unified Communications Manager
205

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)