How to call AS/400 commands from OW

Hi,
We have two separate systems. One is OW other is AS/400. We are in a phase of developing an interface between them.
Regarding this does anybody has any idea how can we call AS/400 commands from OW?

There is an external calls business function..

B34A1030 - execute external program

I believe there are other methods too - you might want to search "external call" under this forum.