Kramer Electronics VS-30FW - Manual (Page 5)

Overview
3
cards that you install inside the computer's case), FireWire devices are
simple. Many peripheral devices (including: DV Camcorders, Digital still
cameras, Storage devices such as External Hard Drives and Disk Arrays,
Network connections, and scanners and printers) now come in a FireWire
version.
Connecting a FireWire device to a computer is easy – you just plug it into the
port. If it is an uninstalled FireWire device, the operating system auto-detects
it and installs software support for it automatically. If the device has already
been installed, the computer activates it and starts talking to it.
With so many FireWire devices on the market today, you easily run out of
ports very quickly. The simple solution to the problem is an inexpensive
FireWire hub. The FireWire standard supports up to 63 devices, and FireWire
hubs are a part of the standard. You plug the hub into your computer, and
then plug your devices (or other hubs) into the hub. By chaining hubs
together, you can build up dozens of available FireWire ports on a single
computer.
A FireWire hub is like a network, with bi-directional signals. The standard
defines FireWire as Peer-to-Peer connection; that is why two devices, or a
device and a computer can talk to each other.
It is important to note that everything depends on your computer’s software,
and the firmware of the devices. Sometimes, it is possible that a computer can
work with many FireWire devices simultaneously (like a distributor),
sometimes it can work with many devices in time-sharing mode (like a
switcher). But most often it is possible to work one-to-one. In this case, you
have to disconnect all the devices that are unnecessary at this time and leave
only two of them. Since the FireWire is hot-plug standard, you can
connect/disconnect devices at any time.
Hubs can be powered or unpowered. The FireWire standard lets devices draw
their power from their FireWire connection. Obviously, a high-power device,
like a professional DV camcorder, will have its own power supply, but
low-power devices like a Webcam derive their power from the bus in order to
simplify them. The power for this (up to 1 amp at 12 volts) comes from the
computer.
If you have several self-powered devices, then your hub does not need to be
powered, as none of the devices connecting to the hub needs additional
power, and the hub itself can derive power from the computer. If you have
many unpowered devices, you probably need a powered hub. The hub has to
be powered from an AC adapter, which supplies power to the bus. The
VS-30FW can supply up to 2.1A to the bus (each port can provide up to 1A).