This 10/100 Fast Ethernet Module (Cisco# WS-X4148-RJ=) is a component of the Catalyst 4000 Modular Series. The module has (48) RJ-45 ports for 10/100BaseTX LAN connections and is used with Catalyst 4003 (3-slot) and 4006 (6-slot) modular chassis, which deliver the benefits of a converged wiring closet to every user in an enterprise or branch office.
Some key capabilities of the Catalyst 4000 Modular Series include: up to 1,024 VLANs with 802.1Q support on all ports; 16,000 MAC addresses; 802.1D Spanning Tree enhancements for deterministic fast failover, including UplinkFast, PortFast, and BackboneFast; up to 8Gbps Fast/Gigabit EtherChannel Aggregation; embedded RMON; per port load balancing and port filtering, and extensive, not to say comprehensive, management and protocol support.