Metric Halo 2882 operating guide - Manual (Page 26)

Mobile I/O User’s Guide
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Devices connected to the FireWire bus are autoconfiguring. You do not need
to set IDs or DIP switches or in any way configure the devices in order to
facilitate communication between devices or to configure of the bus.
FireWire devices on the same bus must be connected in a tree structure with
no loops. This means that devices can be connected to each other in any
order, and any device with multiple ports can act as a chain or a hub for
other FireWire devices, but you should never be able to get from one device
to another by more than one path. If you construct a loop in the bus, it will
not operate properly and you will not be able access some or all of the
devices on the bus.
Although you are able to attach devices in any order on the FireWire bus,
the order of attachment will have an impact on performance. Most current
model FireWire devices support 400 Mbs operation, but many older devices
may only support 100 or 200 Mbs operation. These devices act as a bottle-
neck in the bus and limit the speed of any bus traffic that flows through
them. In order to maximize performance, you want to ensure that low speed
devices are not used to join high speed devices. In practice this generally
means that you should attach your Mobile I/O directly to your computer or
through a high speed hub.
To connect Mobile I/O to your computer simply plug a FireWire cable into
the Mobile I/O and into the computer. The FireWire bus provides a path for
all communication between the computer and Mobile I/O – audio, control
and meter data.
Mobile I/O audio transport takes advantage of FireWire’s support for isochro-
nous transmission, in which the Mobile I/O can reserve a dedicated amount
of bandwidth on the bus for moving audio samples. Since the audio must be
transmitted on a regular basis to ensure continuous playback and recording ,
the isochronous model is perfect.
Control changes and meter data are transmitted using asynchronous transac-
tions on the FireWire bus. This transmission approach makes use of the unre-
served bandwidth on the bus and competes with things like FireWire hard
disk accesses for time. Under normal circumstances this is completely trans-
parent to the user. If the bus becomes overloaded, you may find that disk