Skip to content

UB2 Tech Notes

Intermittent hum heard through speakers or headphones when using a USB2.0 interface


Product: RX6, UZ2, UB2
Version: All
Date Added: 2005-09-22


An intermittent low frequency hum may be heard through headphones or speakers when the output device is being housed in a ZB1 caddie using a USB2.0 interface. The frequency is variable, and the hum may be constantly present or come and go over time. This has been reported with the RX6 but might occur when using other RP/RX devices with the USB2.0 interface. This problem is only found with USB interfaces and disappears when using the gigabit interface.


Upgrade to the Gigabit interface.

zBUSmon returns invalid version numbers when using USB 2.0


Product: TDT Drivers, UZ2, UB2
Version: All
Date Added: 2005-01-24


When using the UB2/UZ2 USB 2.0 interfaces, clicking the Hardware Reset button in zBUSmon will change the version numbers to 65535 and a transfer test will fail.


After using the Hardware Rest button wait 20 seconds, then close and reopen zBUSmon. The correct version numbers should be displayed.

UB2 fails to configure -- one or more caddies not displayed in zBUSmon


Product: UB2
Version: Serial numbers < 2000
Date Added: 2005-01-21


When a system includes two or more UB2s (System 3 USB 2.0 hubs), the second UB2 will fail to initialize. A Windows operating system error will indicate that a USB 2.0 device failed to configure. You will also be unable to view one or more zBUS caddies in the zBUSmon utility's hardware diagram display.


Contact TDT to request a replacement UB2.