Cisco 7960G Administration Guide - Page 120

General Troubleshooting Tips for the Cisco Unified IP Phone Expansion Module 7914 Chapter 8 Troubleshooting and Maintenance Table 8-2 Cisco Unified IP Phone Troubleshooting (continued) Summary Loopback condition. Explanation 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 10H (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_THRESHOLD To resolve this problem, re-enable the port from the switch. General Troubleshooting Tips for the Cisco Unified IP Phone Expansion Module 7914 Table 8-3 provides general troubleshooting information for the Cisco Unified IP Phone Expansion Module 7914. Table 8-3 Cisco Unified IP Phone Expansion Module 7914 Troubleshooting Problem Solution No display on the Cisco Unified IP Phone Expansion Module 7914 Verify that all of the cable connections are correct. Verify that you have power to the Cisco Unified IP Phone Expansion Module 7914. Lighted buttons on the first Cisco Verify that the Cisco Unified IP Phone Expansion Module 7914 is Unified IP Phone Expansion Module 7914 are all defined in Cisco Unified Communications Manager. red. Lighted buttons on the second Cisco Verify that the Cisco Unified IP Phone Expansion Module 7914 is Unified IP Phone Expansion Module 7914 are all defined in Cisco Unified Communications Manager. amber. 8-12 Cisco Unified IP Phone 7960G/7940G Administration Guide for Cisco Unified Communications Manager 7.0 (SCCP) OL-15498-01