The 16-Port OC-3c/STM-1c POS/SDH ISE line card provides the Cisco 12000 Series Internet Routers with 16-155Mbps concatenated POS interfaces on a single card and provides 16-OC3c/STM-1c full duplex single-mode intermediate reach interfaces. The 16-Port OC-3c/STM-1c POS/SDH ISE line card is compatible with any Cisco 12000 series Internet Router that is operating with the following system software: Cisco IOS Release 12.0(21)S1 or a later release of Cisco IOS Release 12.0 S software; Cisco IOS Release 12.0(21)ST or a later release of Cisco IOS Release 12.0 ST software.