The versatility of Cisco 2610-51XM, 2691, 3660, and 3700 series routers is demonstrated by their broad support of E1/T1 connectivity and Integrated Services Digital Network Primary Rate Interfaces (ISDN PRI). Customers continue to deploy E1 and T1 circuits for Wide Area Network (WAN) connectivity, ISDN dial-backup, and digital modem termination in the Power Branch Office Environment. Cisco now makes it possible to terminate T1 and E1 PRI connections in a single network module. The NM-1CE1T1-PRI card coupled with Cisco 2610-51XM, 2691, 3660, and 3700 Series routers, enhances and simplifies customers' WAN connectivity options.The Cisco E1/T1 ISDN PRI Network Module's integrated channel service unit (CSU) provides direct connection to the Telecommunications network, thus allowing customers to consolidate customer premises equipment (CPE). This provides multifunction dial access aggregation, routing functionality, VPN and firewall security, and other capabilities right inside the Cisco router in power branch office environments.