When Connecting Multiple Um-4 Units - Roland UM-4 Owner's Manual

Appendices

2. When Connecting Multiple UM-4 Units

Up to four UM-4 units can be used simultaneously.
Depending on the CPU processing speed, hard disk, memory, or application
performance of your system, it may not be possible to use two or more units
simultaneously.
Adding more USB Connectors
If your computer does not provide enough USB connectors, you will need a USB hub (a
device to increase the number of USB connectors).
Please purchase a commercially available USB hub.
For connections to your computer, refer to the owner's manual for your USB hub.
Connecting Multiple UM-4 Units
fig.04-02.e_80
The UM-4 handles large amounts of data including MIDI messages via USB. If you
are using two or more USB hubs, connect the UM-4 directly to the computer, or to
the first USB hub.
Note of the Connecting Multiple UM-4 Units
When connecting multiple UM-4 units, the order of the MIDI device is assigned in the order
(connection order) in which the computer recognized each UM-4 unit at the time of turning
on the power of your computer or restarting the computer. Therefore, the order of the MIDI
device may be changed when you restart the computer. In order to change the order of the
MIDI device assigned to each UM-4, disconnect the USB cables connected to all UM-4 units
(from the computer or USB hub). Then connect the UM-4 that you want to be the first unit to
the USB connector that had been connected to the UM-4 previously recognized as the first
unit. Make connections in the same way for the second and subsequent units.
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