With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
x25DteOpTable
x25 Dte Operation Table
1.3.6.1.4.1.562.2.4.1.90.27
This group contains the operational status of the X.25 interface.
Back to Nortel-Magellan-Passport-X25DteMIB MIB page.
IPHost Network monitor allows you to monitor x25DteOpTable on Allied Telesis device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Nortel switches right now.