Envision Peripherals NV3128 - Manual (Page 18)

NV3128 RS-422A Machine-Control Data Switch 1-8
Video equipment offers a sufficient diversity of control options to add another
layer of complexity to routing.
The Sony BVU machines have a single D connector for both controlling and
controlled traffic. The direction of data traffic is controlled by the remote
switch.
The Sony BETA machines hard wire two D connectors together, again for both
controlled and controlling traffic. Although the second connector facilitates
daisy-chained control, it does nothing to diminish the probability of bus
contention this feature invites.
D1 and D2 VTRs use two D connectors, configurable with software as
controlled or controlling. Additionally, these machines can resolve their
involvement in bus contention in a daisy-chained control configuration.
Traditionally, installations have resorted to relay routers or analog audio
routers to switch machine control data, and have just had to tolerate the
limitations and expense caused by the logistical complexity. Analog audio
routers and relay routers share three further disadvantages: They take up a lot
of space, they use a lot of electricity and they cost a lot money.
A SOLUTION:
The NV3128 fully addresses the idiosyncrasies of routing RS-422A machine
control data. Its compact, eight rack-unit frame is small enough to be installed
in the suite. Its 65 watt off-the-line power requirement is less than most light
bulbs. And its cost is a fraction of alternative solutions. Capable of NRZI data
rates up to 5 Mbits/Sec., it offers 128 I/O ports in a non-blocking X-Y matrix.
It is also available in a 64-port configuration that can be field upgraded to 128
ports by simply adding an additional I/O module.