Sierra Video G.R.I.P. V3.1.0 - Manual (Page 59)

GRIP 3.1.0
53
Planning the Router Size and the Mapping Tables
Before actually making changes to the router mapping tables, spend time working out the
desired mapping scheme. To do this, a brief introduction to the Sierra Video Systems
virtual mapping scheme is useful.
Rough out the mapping tables on paper first. The basic tasks are to decide which router
inputs will receive signals from which machines; likewise for the outputs; choose names
for each of these input and output signals; decide which source numbers are to be
assigned to each input connector on each level; and likewise which destination numbers
are to be assigned to each output connector on each level.
Keep multiple mapping possibilities in mind (assigning multiple sources numbers to the
same input connector).
Give each input and output signal that is to be connected to your router a name. Names
can be up to 8 characters (including spaces) to allow control panels and programs to
display information compactly and succinctly. Every input and output signal must have a
UNIQUE name, there should be no duplicates. Usually the name of the device that the
signal comes from or goes to is used as the signal name.
A different name may be chosen for each level of the router, although often the same
name is used. For example, in a three-level router with one video and two audio levels,
signals from a VTR might be named VTR1 on all three levels. Usually, the physical input
signal names will be what the user sees when status is displayed for a crosspoint. The
physical output signal names currently have little significance, although some control
systems may choose to make use of them.
When choosing names, use prefixes with numeric suffixes as much as possible, e.g.
“CAM1”, “CAM2”, “CAM3”, so that mnemonic control panels with a limited number of
buttons for selecting a prefix (CAM) can be effectively used. Names can contain any
printable ASCII characters, including spaces and both upper and lower case letters, but
they cannot include “*” or “!” or “~” characters. Sometimes spaces can be a problem, if a
name has a space and the user enters the name without one, the control panel may not
be able to find it (and vice-versa).
Decide which signals are to be grouped together (on different levels) under a single
physical input or output connector number. Usually this is obvious: the signals (e.g. video
and audio) going to or coming from a device are normally grouped together. Sometimes,
though, a device has only one form of signal, e.g. a graphics workstation might process
video signals but not audio. There are at least a couple cases to consider:
1. Some signals come from or go to one device, while the remaining ones come from or go to
another device, but the entire set of signals is normally switched as a group. Example: video
signal from a workstation that is normally used together with an audio signal from an audio
“sweetener” device of some sort.
2. A device supports only some of the signals, e.g. video only; in order to not waste router inputs
or outputs, the other router levels (e.g. audio levels) of the router input or output connected to
that device will be used by some other device that only supports those other signals (e.g. only
supports audio signals). Normally the two sets of signals are NOT switched together, but they
are nevertheless assigned to the same router input or output connector number (on different
levels) so as not to waste router inputs/outputs.
In either case (1) or (2), all the signals are assigned to a single physical input or output
connector number.
These signal groupings are actually not a rigid requirement, because the mapping tables
allow signals to be regrouped at will. Thus, for example, although it would be typical (and
recommended) to place the video and audio signals from VTR1 together under the same