When attempting to troubleshoot cellular or PPP connections, detailed packet tracing can be extremely helpful for diagnosing possible causes. The following steps outline how to obtain a trace on the PPP1 interface:
Management– Analyser > Settings.
Layer1 (Physical), Layer 2 (Link), and Layer 3 (Network)
Administration - File Management >Flash Directory.
file which can be sent to Digi Tech. Support for analysis.