Adtran Atlas 550 Quad ISDN BRI U Module 1200315L1 Modules or whatever you have programmed

or whatever you have programmed

and line appearances

and a stateful inspection firewall

It provides four EIA-232 or V

The network switch is capable of supporting up to 232 Gbps of switch fabric capacity and has a forwarding rate of 131 Mpps

Adtran Atlas 550 Quad ISDN BRI U Module 1200315L1 Modules or whatever you have programmedAdtran Atlas 550 Quad ISDN BRI U Module 1200315L1 Description: The Adtran 1200315L1 provides 4 ISDN U Interfaces for User Termination applications. The Quad ISDN BRI U module supports AT&T 5ESS, Nortel DMS 100, and National ISDN 1. The Adtran 1200315L1 is compatible with Atlas 550 gateways. Adtran 1200315L1 Features: Provides four BRI S T interfaces Supports: AT&T 5ESS Nortel DMS 100 National ISDN 1 Can only be used in a user interface module slot.