... that leverages the interoperability, scalability and enhanced services capability of industrial standard SIP protocol. Flexible configuration of one to four E1 / T1Guarantee ... , Remote Software Upgrade, Alarm, Performance DataSignaling· PSTN Side ISDN PRI Standard: ANSI, NI-2, DMS, 5ESS· VoIP ProtocolSIP (RFC3261) , 2976 Info ...