Except for environments with very fast terminals, controllers, and
lans, filter control is likely to add noticeable delays. Since even
delays of 1/10
thof second are noticeable, filter control should be
used as infrequently as possible on as few devices as possible.
Note that it is not required to be in control of a device to be
able to send data to it.
Full time filter control of the scanner, keyboard, display or
printer, especially for a large number of terminals in a live store
environment, can cause noticeable sales application delays. Filter
control means that each keystroke, scan, display or print must make
a round trip from the terminal to the controller agent, to the
filter client and back again. The design intent of the InSight
DataWatch facility is to allow a mechanism for filter applications
to only filter device data in limited situations. Using
FilterClientControlTableDevicesToFilter, a filter client can
dynamically turn on and off filter client control of a particular
device.