This is a 10/100/1000BASE-T Fast Ethernet switching module for the Catalyst 4900M Switch (available separately) & is used in one of the two half-card slots of the switch. The module supports half or full duplex mode & features (20) RJ-45 connector ports with port speeds of 10, 100 or 1000 Mbps. Power-over-Ethernet (Po E) is not supported