The following resolved this particular problem:
How it works
The Aristel PABX operates on baud rate 2400.
The Buffer Sends the data to PABX3 on 9600
PABX3 must receive the data on 9600
Settings
In PABX3 -> Option -> Communications. Make sure the baud rate is 9600.
Click START -> Control panel -> System -> Hardware -> Device manager.
Right click on comport 1 and select
Click on the 'settings'tab.
Make sure the baud rate is 9600.
Open PABX 3 -> Tools -> VT100 and make a test call. You should see the call on your VT100 screen.
If data can be seen in VT100 but not on PABX3 call data screen, Open VT100 and type in:
SQ 0 Followed by Enter to disable number sequencing.
Make another test call.