Avaya Definity TN2401 Net/Pkt Interface - R9si or later (Refurbished)Avaya Definity TN2401 Net Pkt Interface (R9si or later). More Information In R9si systems, the TN2401 Net Pkt interface replaces the TN794 Provides the functionality of the TN777B network control interface (NETCON), the TN778 packet interface (PACCON, and, if BX. 25 connectivity is not required, the TN765 Processor interface (PI) Inserts into control carrier slot that was used by NETCON TN777B Required for the si model to save translations to the new