With IPHost Network Monitor you can run simple snmp requests against a Nortel device in your network.
gsmBcModemOutbandFlowControl
gsm Bc Modem Outband Flow Control
This attribute indicates whether inband or outband flow control conversions are being performed. The modem performs either inband or outband flow control unless V.42 layer is active, it is a fax call, or no flow control was specified by the MSC.
Back to Nortel-Magellan-Passport-GsmIwfMIB MIB page.
IPHost Network monitor allows you to monitor gsmBcModemOutbandFlowControl 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.