Functions include Packet Bus reconfiguration that allows diagnosis and correction of recoverable Packet Bus failures before Link Access Procedure on the D-Channel (LAPD) links fail - ISDN - PRI testing that originates and terminates loopback tests on ISDN facilities
TN 771D is required in all standard reliability Primary Port Networks (PPNs) and critical reliability Expansion Port Networks (EPNs). All standard reliability PPNs when packet endpoints (BRI and/or ASAI) are supported
