The OC-12c dynamic packet transport (DPT) port adapters are dual-width OC-12c port adapters that provide a shared IP over Synchronous Optical Network (SONET) capability. The DPT port adapters are available in three models: multimode fiber, single-mode fiber intermediate reach, and single-mode fiber long reach.The DPT port adapters provide the Cisco uBR7246 universal broadband router with two SC duplex ports. Each SC duplex port provides the physical connection to a device in a SONET OC-12 DPT ring. DPT rings can also be connected to SONET add-drop multiplexers (ADMs), thus allowing for the creation of small or very large DPT rings.