With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
x25DtePeerCallingNetworkFax
x25 Dte Peer Calling Network Fax
1.3.6.1.4.1.562.2.4.1.90.2.12.1.24
This attribute specifies the Calling Network facilities to signal in a call request packet. The facilities are encoded here exactly as they are encoded in the call packet. These facilities do not include the marker facility code. A value of null (empty string) indicates the callingNetworkFax from the X25Dte are to be signalled. If that value is also null, no Calling Network Facilities are signalled.
Back to Nortel-Magellan-Passport-X25DteMIB MIB page.
IPHost Network monitor allows you to monitor x25DtePeerCallingNetworkFax 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 multiplexers right now.