Cisco offers a variety of connectivity, expansion and upgrade modules and cards to accommodate the customer specific needs. Cisco's components are easily and inexpensively upgradeable as customer requirements change.The Cisco OC-12/STM-4 packet-over-SONET/SDH line card is a high-capacity, high-performance interface that enables service providers to substantially increase the data load on their existing fiber networks. The OC-12/STM-4 is ideal for edge feature support and can be configured with multimode and single mode intermediate reach optics enabling customers to connect directly to traditional SONET/SDH solutions.