Cisco 7970G Administration Guide - Page 252

General Troubleshooting Tips Chapter 9 Troubleshooting and Maintenance 9-18 Table 9-2 Cisco Unified IP Phone Troubleshooting (continued) Summary Explanation Loopback condition A loopback condition can occur when the following conditions are met: • The SW Port Configuration option in the Network Configuration menu on the phone is set to 10 Half (10-BaseT/half duplex) • The phone receives power from an external power supply • The phone is powered down (the power supply is disconnected) In this case, the switch port on the phone can become disabled and the following message will appear in the switch console log: HALF_DUX_COLLISION_EXCEED_THRESHO LD To resolve this problem, re-enable the port from the switch. One-way audio When at least one person in a call does not receive audio, IP connectivity between phones is not established. Check the configurations in routers and switches to ensure that IP connectivity is properly configures. Peer to peer image distribution fails. If the peer to peer image distribution fails, the phone will default to using the TFTP server to download firmware. Access the log messages stored on the remote logging machine to help debug the peer to peer image distribution feature. Note These log messages are different than the log messages sent to the phone log. Cisco VT Advantage/ If you are having problems getting CVTA to work, Unified Video Advantage make sure that the PC Port is enabled, and that CDP (CVTA) is enabled on the PC port. Cisco Unified IP Phone 7970G/7971G-GE Administration Guide for Cisco Unified Communications Manager 6.1 OL-14626-01