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5 1394 Interface
Digital image information is transferred from the STH-MD1/-C to the host
PC via a 1394 cable. The cable sends a video stream from the imagers to
the PC, and sends commands from the PC to the stereo head to control
exposure, subsampling, etc. The cable also supplies power to the stereo
head.
5.1 1394 Cable
The STH-MD1/-C must be connected to the host PC via a 6-pin male-male
IEEE 1394 cable. The maximum length for such a cable is 4.5 m (about
15 feet). The cable supplies both signals and power to the stereo head.
Use only one cable!
The two ports on the MEGA-D are for daisy-chaining
additional devices onto the IEEE 1394 bus.
The distance between the stereo head and the PC can be extended by using
a 1394 repeater.
Several 1394-enabled devices can be connected together, as long as the
connection topology doesn’t have any loops. The STH-MD1/-C can be
connected at any point in such a topology. At a maximum, it will need
about 60% of the bandwidth of a 400 MBps connection.
5.2 1394 Host Interface
The host computer must have an available 1394 port. Some portables and
desktops come with built-in ports. If these are 6-pin ports, they can be
connected directly to the STH-MD1/-C. Sony laptops also support an
alternative 4-pin 1394 cabling, which has the signal pins but no power.
There are adapters that convert from 4-pin to 6-pin styles; these adapters
use an external power supply transformer.
If the host PC doesn’t have a built-in 1394 port, one can be added by
installing a 1394 PCI card or PCMCIA card for laptops. 1394 PCI cards
have 6-pin ports, and supply power. PCMCIA cards do not have the
capability of supplying power, and come with an adapter for supplying
power to the 1394 cable through a wall transformer.
Any 1394 card is suitable, as long as it conforms to OHCI (open host
controller interface) specifications. All current cards do, but some older
cards may not.
