The CP, is the central processor, the major control part of the AXE,
The APG is the adjunct processor, belongs as well to the control part.
The CP contains, the Dump, the configuration,of your AXE
The APG, collect and send the data from your AXE to a remote site (OMC)
the data, could be statistics, CDR, dump, etc…
Basically you need an APG to access to your AXE.
APG use an Microsoft OS,
And we have different type of HW
APG40C/2, APG40C/4, APG43
In resume APG is the Input-output system of your AXE, and The CP is the Calculator