The Cisco® 10GBASE X2 modules (Figure 1) offers customers a wide variety of 10 Gigabit Ethernet connectivity options for data center, enterprise wiring closet, and service provider transport applications. Features: -Supports 10GBASE Ethernet. -Hot-swappable input/output device plugs into an Ethernet X2 port of a Cisco switch or router to link the port with the network. -Provides flexibility of interface choice. -Supports "pay-as-you-populate" model. -Supports the Cisco quality identification (ID) feature that enables a Cisco switch or router to identify whether the module is a Cisco.certified and tested X2. -Optical interoperability with respective 10GBASE Xenpak and 10GBASE XFP modules on the same link. The Cisco 10GBASE-CX4 Module supports link lengths of up to 15 m on CX4 cable.