When the PCU is in external mode, you can trace the messages on the Pb interface on the BSC6000 Local Maintenance Terminal. This describes how to trace the application messages and LAPD messages on the Pb interface.
Tracing Application Messages on the Pb Interface
This describes how to trace application messages on the Pb interface on the LMT. The messages consist of paging message, confusion message, PCIC message, and other messages.
Tracing LAPD Messages on the Pb Interface
This describes how to trace the layer 2 messages on the Pb interface through the LMT. You can trace the LAPD messages on the Pb interface based on the specified link.