Cisco WS-X6904-40G-2T= network switch module

Cisco® Catalyst® 6500 Series Switches offer a variety of Ethernet modules to serve different needs in the campus and data center for enterprise, commercial, and service provider customers. The Cisco Catalyst 6904 4-Port 40 Gigabit Ethernet Fiber Module (Figure 1), fully compliant with the IEEE 802.3ba standard, complements this product portfolio.
The module is designed to meet the increasing demand for aggregation of 10 Gigabit Ethernet on campus and data center, as well as for high-density 10 Gigabit Ethernet and 40 Gigabit Ethernet transport in the core.

Each port can accept a 40 Gigabit Ethernet C Form-Factor Pluggable (CFP) optics module or be converted to four ports of 10 Gigabit Ethernet with a FourX adapter, enabling customers to deploy 10 Gigabit Ethernet to meet current needs and be ready to transition to 40 Gigabit Ethernet without any disruption. The module can also be used in mixed mode, where one side of the card uses two CFP modules for 2 times 40 Gigabit Ethernet ports and the other side uses two FourX adapters for 8 times 10 Gigabit Ethernet ports.

The Cisco Catalyst 6900 Series 4-Port 40 Gigabit Ethernet Fiber Module is compatible only with Cisco Catalyst 6500 Supervisor Engine 2T.