The PA-SRP-OC12 series Dynamic Packet Transport (DPT) port adapter is a dual-width OC-12c/STM-4 port adapter that provides a shared IP over Optical capability in Cisco 7200 Series, Cisco uBR7246, Cisco uBR7246VXR or Cisco 7200 VXR Series routers. The DPT port adapter provides two SC duplex ports. Each SC duplex port allows connection to an adjacent device in a DPT ring. The DPT port adapter is designed to be deployed in SONET OC-12c/STM-4 DPT rings. DPT rings can also be connected to SONET add drop multiplexers (ADMs), thus allowing for the creation of small or very large DPT rings. DPT is media-independent, capable of operation over dark fiber, SONET/SDH gear and WDM infrastructure.