The OMS emulator extension is quite old but it allows you to use Freemidi impersonating OMS. OMS need not be installed... in this case Freemidi is the only one running. I know with this scenario Logic 4 versions work, though I would not go that route. The other way is to use OMS (i.e. for Sounddiver), and choose use OMS in Freemidi prefs. This way Freemidi (i.e. for DP) is slaved to OMS. Personally I never found Freemidi to be friendly or stable, especially on SCSI Macs. I have run OMS with Logic and Sounddiver and Unisyn simultaneously without any problems. Note, however, I don't record audio or use VSTs on my sequencing MDD with Logic. If I were to run DP or Unisyn that require Freemidi, I would choose use OMS if available in Freemidi prefs.
Keyspan PCI is solid.... very little jitter on a rig with hardware racks. USB is a power drain and doesn't handshake without delay. But if you've got it to work for you, by all means stay with it. There are so many variables....
Two Studio 5's networked would use M1-M30 on a real modem port without OMS. But only the sum input works even without OMS. My point is that the individual inputs do not work in Logic 5&6. Individual outputs always work, no problem.
There are many things in Logic that will make no sense until you use it enough and discover that in Logic there is ALWAYS a workaround. My favorite is the alert box: "Circular Structure! Please report to Emagic how you did this!" ( You will see that you are now recording in the trash folder or some such nonsense.)
So everyone who sees that alert should call Apple and report it. That'll teach them for buying out Emagic.....
Syntho, I'm aware of how things are supposed to work, as you describe. I'm only talking about input cables not working, i.e. M1-M32 and P1-P32.
How about a screenshot of the monitor showing data and connected to M1-M8 physical inputs using OMS? Just kidding.... it was one of those steps down in the evolution of Logic from version 4. But it really is only significant if you are inputting multiple hardware device data...things could get messy at only the sum input.