Adtran has applied its industry-leading carrier class expertise to the OCU 45, creating a product that meets the most stringent carrier class requirements. The OCU 45 offers transparent transport of T3/E3/STS-1 services over point-to-point dark fiber, at distances up to 40km. The OCU 45 is available in single-mode and multi-mode versions. Measuring only one rack unit high, the OCU 45 can be used standalone, wall-mounted or mounted in 19-inch or 23-inch racks using an optional mounting tray. This compact device gives network service providers a convenient way to extend T3/E3/STS-1 services from their point-of-presence to the customer. It provides the enterprise user with a powerful tool for extending services in campus applications or in inter-building risers.