Cisco 3825 Hardware Installation Guide - Page 240

Connecting to the EtherSwitch Service Module Ports Chapter 18 Connecting Cisco EtherSwitch Service Modules For the Cisco 3745 router, the following specifications apply: • These routers can have one or two internal -48 V power supplies. The internal supplies of these routers are configured to be redundant by default. • With a single power supply, these routers can provide up to 360 W. This is enough power for up to forty-eight 7-W IP phones. Power Considerations for the Service Module The Cisco EtherSwitch service module supports inline powering of IP telephones with -48 V power. This allows IP phones to be plugged into a standard RJ-45 jack and be powered from the switch rather than from an AC wall outlet. Caution To comply with Telcordia GR-1089 NEBS, this product is suitable for connection to intrabuilding or nonexposed wiring or cabling only. The intrabuilding cable must be shielded and the shield must be grounded at both ends. The Cisco EtherSwitch service module distributes the -48 V power to each of the Ethernet ports that are configured for PoE. Each port can be independently configured for PoE. Powering Considerations for a Switch Stack Consider the following guidelines before you power the Cisco EtherSwitch service modules in a stack: • The sequence in which the Cisco EtherSwitch service modules are initially powered up might affect the Cisco EtherSwitch service module that becomes the stack master. • If you want a particular Cisco EtherSwitch service module to become the stack master, power up that Cisco EtherSwitch service module first. This Cisco EtherSwitch service module becomes the stack master and remains the stack master until a stack master re-election is required. After approximately 10 seconds, power up the other Cisco EtherSwitch service modules in the stack. • If you have no preference about which Cisco EtherSwitch service module becomes the stack master, power up both Cisco EtherSwitch service modules in the stack within 10 seconds. These Cisco EtherSwitch service modules participate in the stack master election. Connecting to the EtherSwitch Service Module Ports Fast Ethernet (FE) ports are used to connect PCs or workstations to the network. A 10/100/1000 Gigabit Ethernet (GE) port or a SFP module port can be used as an uplink port to connect to another router or a server, or can trunk to another Cisco EtherSwitch service module or switch located in the same chassis or in a separate installation. Connecting a FE or GE port to the network requires a Category 5 cable with RJ-45 male connectors, not provided with the network module. Category 5 cables are widely available. 18-14 Cisco Network Modules Hardware Installation Guide OL-2485-20