Cisco 7609-S Software Configuration Guide - Page 228

Understanding Cisco IP Phone Support Chapter 16 Configuring Cisco IP Phone Support Inline-Powered Cisco IP Phones Inline power is from switching modules that support an inline power daughtercard. Inline power is sent over the twisted-pair Ethernet cable to the Cisco IP phone. Note For information about switching modules that support inline power, refer to the Release Notes for Cisco IOS Release 12.2SX on the Supervisor Engine 720, Supervisor Engine 32, and Supervisor Engine 2. When a switching module port detects an unpowered Cisco IP phone, the switching module reports to the supervisor engine that an unpowered Cisco IP phone is present and on which module and port. If the port is configured in auto mode, the supervisor engine determines if there is enough system power available to power up the Cisco IP phone. If there is sufficient power available, the supervisor engine removes the default-allocated power required by a Cisco IP phone from the total available system power and sends a message to the switching module instructing it to provide power to the port. If there is not enough available power for the Cisco IP phone, the supervisor engine sends a message to the switching module indicating that power is denied to the port. Cisco IP phones may have different power requirements. The supervisor engine initially allocates the configured default of 7 W (167 mA at 42 V) to the Cisco IP phone. When the correct amount of power is determined from the CDP messaging with the Cisco IP phone, the supervisor engine reduces or increases the allocated power. For example, the default allocated power is 7 W. A Cisco IP phone requiring 6.3 W is plugged into a port. The supervisor engine allocates 7 W for the Cisco IP phone and powers it up. Once the Cisco IP phone is operational, it sends a CDP message with the actual power requirement to the supervisor engine. The supervisor engine then decreases the allocated power to the required amount. When you power off the Cisco IP phone through the CLI or SNMP or remove it, the supervisor engine sends a message to the switching module to turn off the power on the port. That power is then returned to the available system power. Caution When a Cisco IP phone cable is plugged into a port and the power is turned on, the supervisor engine has a 4-second timeout waiting for the link to go up on the line. During those 4 seconds, if the Cisco IP phone cable is unplugged and a network device is plugged in, the network device could be damaged. We recommend that you wait at least 10 seconds between unplugging a network device and plugging in another network device. Other Cisco IP Phone Features The Cisco 7600 series router provides support for authentication, authorization, and accounting (AAA) for Cisco IP phones, as described in Chapter 46, "Configuring IEEE 802.1X Port-Based Authentication." The Cisco 7600 series router also supports automatic tracking for Cisco Emergency Responder (Cisco ER) to help you manage emergency calls in your telephony network. For further information, see this URL: http://www.cisco.com/en/US/products/sw/voicesw/ps842/tsd_products_support_series_home.html 16-4 Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX OL-4266-08