If it's running DOS it should be a reasonable i386 compatible machine. If you have a spare slot (pci/isa) I would install an internal modem or an extra networkcard and reinstall the whole thing with Linux or *BSD (console only, no X-Windowing System).

Edit: Hmm. Just got a brainwave. I think IPADs where used to connect to an X.25 network. That's probably why it isn't there anymore (X.25 modems were usually external). There's no real use for X.25 modems anymore (eventhough some companies still operate them) so they probably threw that away.