Cisco Systems, Inc. is the worldwide leader in networking for the Internet. Cisco products include routers, LAN and ATM switches, dial-up access servers and network management software. These products, integrated by the Cisco IOS software, link geographically dispersed LANs, WANs and IBM networks. Cisco offers a variety of expanding modules for Cisco routers to upgrade its abilities in order to meet growing demands of modern networking communications. The astonishing versatility of the Cisco router series is highlighted by its broad support of Integrated Services Digital Network Primary Rate Interface (ISDN PRI) connectivity.The network modules provide various port densities to meet customer requirements at various price points. One-port Channelized T1/ISDN PRI network module provides up to 24 virtual channels per T1 port.