The SPD-30 has a Computer USB MIDI port for connecting directly to the computer. This port can be used for transmitting/receiving MIDI Note Number data, velocity messages, CC messages and PC messages, and is convenient for triggering sounds and/or sequencing in the computer without having to use a separate external USB > MIDI Interface.
For setup, use a standard (A-B) USB cable and connect the USB "MIDI" port on the back of the SPD-30 to an available USB port on your computer. It's preferred to connect directly to a physical port on the computer, and not to a USB hub.
Generally, it's not required to install the SPD-30 USB drivers, however if you experience problems, downloading and installing the SPD-30 USB drivers would be recommended. You can find them available here:
http://www.rolandus.com/products/octapad_spd-30/downloads/
Once the drivers have been installed, be sure to set the SPD-30's USB driver mode to "VENDOR." Here's how:
1. Press MENU.
2. Turn the function 1 knob to highlight "SYSTEM," and then press the function 3 button (ENTER).
3. Press the function 2 button to choose the MIDI tab.
4. Turn knob 1 to select "USB Driver," and then turn knob 3 to choose "VENDOR."
5. Press EXIT when you're finished. The new settings are saved automatically.
6. Connect the USB cable to the computer, and then cycle the power on the SPD-30 (Off/On).
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With this setup, you'll be able to select the SPD-30 as the "MIDI device" within your software.
If necessary, you can follow the steps from the following Knowledge Base entry to assign specific MIDI Note Numbers to each pad;
http://www.rolandus.com/support/knowledge_base/201919729
Note, that it's not possible to transmit audio signals from the SPD-30 to the computer via its USB port. If you want to record the sound (audio) of the SPD-30, connect its 1/4" main outputs to the audio inputs on your computer audio interface.