The Cisco® 10GBASE X2 modules offer customers a wide variety of 10 Gigabit Ethernet connectivity options for data center, enterprise wiring closet, and service provider transport applications. Main features of Cisco 10GBASE X2 modules include: - Support 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 certified and tested by Cisco. - Has optical interoperability with respective 10GBASE Xenpak, 10GBASE XFP and 10GBASE SFP+ modules on the same link. Cisco X2-10GB-ZR: Supports link lengths of up to about 80 km on SMF. This interface is not part of the 10 Gigabit Ethernet standard but is built according to Cisco optical specifications.