Cisco 12000 Series 6-port and 12-Port DS3 Line Cards are designed to simplify the deployment of DS3 services. These line cards allow the Gigabit Switch Router (GSR) to be connected to high-speed DS3 leased line service. With these line cards and the existing Cisco optical-based channelized OC-12 line card, a network designer can select either an optical or electrical-based solution for high-speed customer access.