If you don't got for USB-AUDIO, look here 05/07/00
Emagic has announced the arrival of MIDI Transmitter Four - MT4 - a USB MIDI interface for both Mac and Windows. It's a low-cost, lightweight USB-only MIDI interface with two inputs and four outputs, all independently addressable for a maximum of 32 channel input and 64 channel output.
The MT4 has two MIDI In activity LEDs and four MIDI Out activity LEDs, and a programmable Patch Mode that enables for stand-alone use as a MIDI patchbay. Using the included software, up to 32 patch configurations can be stored and are switchable via MIDI Program Change. Patch Mode is indicated by its own LED, as is USB activity.
The MT4 is directly supported in the Logic Audio Mac series and can also be
addressed via OMS. How low cost, you ask? $149, Emagic replies.