We do not yet have an adapter to allow JobScheduler to work with IBM AS/400 & System i machines.
However, there are possible workarounds:
You can install an OpenSSH server on AS/400 and use JobScheduler's SSHJob2JSAdapter - one of our - to start the jobs.
Using a Trigger file & file watcher
If you can install a file watcher on the IBM machine to monitor a file or folder, you can then use JobScheduler to transfer a trigger file.