Instruction manual

FireWire
PIKE Technical Manual V3.1.0
21
Compatibility between 1394a and 1394b
Compatibility example
It’s possible to run a 1394a and a 1394b camera on the 1394b bus.
You can e.g. run a PIKE F-032b and a MARLIN F-033b on the same bus:
• PIKE F-032b @ S800 and 120 fps (5120 bytes per cycle, 64% of the
cycle slot)
• MARLIN F-033b @ S400 and 30 fps (1280bytes, 32% of the cycle slot)
Bus runs at 800 Mbit/s for all devices. Data from Marlin’s port is up-converted
from 400 Mbit/s to 800 Mbit/s by data doubling (padding), still needing 32%
of the cycle slot time. This doubles the bandwidth requirement for this port,
as if the camera were running at 60 fps. Total consumption is thus 5120 +
2560 = 7680 bytes per cycle.
1394a camera connected to 1394b bus
The cable explains dual compatibility: This cable
serves to connect an IEEE 1394a camera with its
six-pin connector to a bilingual port (a port which
can talk in a- or b-language) of a 1394b bus.
In this case the b-bus communicates in a-language
and a-speed with the camera achieving
a-performance
1394b camera connected to 1394a bus
The cable explains dual compatibility: In this case,
the cable connects an IEEE 1394b camera with its
nine-pin connector to a 1394a port.
In this case the b-camera communicates in
a-language with the camera achieving
a-performance
Figure 4: 1394a and 1394b cameras and compatibility
1394a camera
1394b port
1394a port
1394b camera