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DAT 160 USB
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7 USB configuration Guide
In this chapter:
– “USB in DAT devices” on page 37
– “USB terminology” on page 37
– “Setting up a USB network” on page 39
– “USB cables” on page 39
7.1 USB in DAT devices
The DAT tape drive is a USB 2.0 logo certified device. It supports the high-speed
USB transfer rate with a theoretical maximum transfer of over 50 MB/s. (The
actual backup rate will be less. This is defined by the transfer rate of the tape
drive and the compressibility of the data.)
To benefit from the high-speed performance of the USB 2.0 interface, the USB
DAT tape drive should be connected to its host system via a USB 2.0 port. Any
USB hubs between the tape drive and the system port should also be USB 2.0
compliant.
To maximize tape drive performance, minimize the use of other USB devices
when using the USB tape drive.
7.2 USB terminology
The Universal Serial Bus, USB, is a communication interface where an intel-
ligent host controls all the network activity. A command from the host to a
particular device is broadcast to all devices on the network. A device waits for a
command addressed to itself and then responds as requested. The host deter-
mines how much of the overall USB network bandwidth a given device can use
at any time. Any given USB network has only one host.
Hubs act as command repeaters and multipliers. This allows many devices to
be supported by one host. A host command can arrive at the upstream port of
the hub and be transmitted via the downstream ports to many other device and
hubs. (Likewise, device commands arriving at a downstream port are also
repeated upstream.) There is a special hub called a root hub. The root hub’s