MIDEX-8
English – 35
ENGLISH
Using USB Hubs
Simple and small USB devices sometimes offer facilities to pass on the
USB signal. Because of its more complex tasks and higher power
requirements, the MIDEX-8 has been designed as a USB end device. If
you wish to simultaneously operate several MIDEX-8 on one USB port,
you require a USB hub.
A USB hub is an additional device, which offers at least one USB input
and two USB outputs. A hub “distributes” the incoming data onto the
connected devices.
Two different types of device are available on the market: “self-pow-
ered USB hubs” (i.e. hubs with their own power supply) and “bus-pow-
ered USB hubs” (i.e. hubs that get their power from the USB bus of the
computer).
If you wish to connect one or several MIDEX-8 to a hub, it must at least
be able to supply 500 mA per USB port.
If connected to a self-powered USB hub, the MIDEX-8 doesn’t need an
external power supply. According to the USB specification, each port of
such a hub should be able to supply at least 500 mA, which is enough
to run a MIDEX-8.
If connected to a bus-powered USB hub, each MIDEX-8 must be sup-
plied with power using an external power supply. Hubs of this type get
the necessary power exclusively from the computer’s USB bus. Accord-
ing to the USB specification, the outputs of such a hub do supply a
maximum of 100 mA, which is not enough to operate a MIDEX-8.
❐
If necessary, the operating system will inform you about possible over-
load problems in the USB bus power supply and suggest something like
“Connect your MIDEX-8 to an external power supply!”. Follow this sugges-
tion to remedy the problem.
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