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-3/STM-1 Packet-over-SONET/SDH Line Card is a high-capacity, high-performance interface that is ideal for edge feature support and customer access applications. The four-port OC-3/STM-1 card may be ordered with multimode, single mode intermediate reach, and single mode long reach optics enabling customers to connect directly to fiber or traditional SONET/SDH solutions.