There are several source and destination signals that are generated when a surface is
added to a Wheatstone Bridge Router system or SAT cage. These signals generally start
at signal ID 1000 for both sources and destinations. What follows is a listing of the
names of the signals generated along with descriptions of their functions and uses within
the system.

First, a brief word about the names themselves. The names typically begin with the
letter "G" followed by a number from 1 to 9, and then followed by the rest of the name
to identify the signal uniquely. The number refers to a specific surface. For example,
G1 prefixed names would most likely be associated with the first G-series surface in a
system, G2 for the second, etc. In the signal descriptions below we use "Gx" as the
prefix to be generic about it.

The following screenshot shows the Xpoint matrix with the surface signals for a single
G-4 surface shown. Refer to this figure, or run Xpoint and refer to your own screen, as
you read through this document.

We'll start with the sources. Since these are sources to the audio cards in the system
they actually represent audio outputs from the surface (Logic signals are a different
breed of animal and will be dealt with separately.)

The first audio sources (surface outputs) are fairly obviously named. GxPGM, GxAUD,
GxAUX, and GxUTL represent the four main bus outputs: Program, Audition,
Auxiliary, and Utility, respectively. These sources must be connected via crosspoint to
the audio output card signals that will be used to feed the buses to any external
equipment, such as, for example, the program output feeding an STL.

GxMxM01 through GxMxM08 represent the eight mix minus outputs. When the
surface is first added to the system these can be defined as either mono or stereo signals.
Once again, to be useful, these signals must be connected via crosspoint to the audio
output card signals used to get them out of the system.

Next come the monitors. GxSTD1 and GxSTD2 are the Sudio 1 and Studio 2 outputs,
respectively. GxHP is the Headphone output. GxCR is the Control Room output.
There are two cue outputs, GxCUE, which is post-level-control, and GxCUEM (pre-
level-control). All of the monitor outputs can be independently set for mono or stereo
when the surface is first added to the configuration, except that the CUE and CUEM
outputs must both be mono or both be stereo. Once again, crosspoint connect these
signals to the desired audio output cards.

The last audio source is GxWCMIX. This surface output is the same as the audio that is
feeding the switched meters. It is configured as a stereo signal, and must be crosspoint
connected to an audio output card to be of use.

Audio Destinations
In a similar manner to the sources, the destinations receive audio signals from the
system, and so are inputs to the surface.

The first destinations are the signals that represent the feeds to the monitors. When a
signal is routed to a monitor, a crosspoint is made between that signal and the pertinent
monitor destination. For example, if you are monitoring the surface Program output on
the Studio 1 monitor, then there will be a crosspoint between GxPGM and the first
monitor destination, GxST1Ex. This happens whether you dial up a source, use a
predefined monitor source button, or go to Xpoint and place a crosspoint there.

As already hinted, GxST1Ex is the input to the Studio 1 monitor. Likewise, GxST2Ex
is the input to Studio 2, GxHPExt the input to the Headphone monitor, and GxCRExt
the input to the Control Room monitor. GxMeter is the input to the switched meters.
GxTBack is the input to the surface's Talkback bus. If you want, say, Mic1 (a source) to
be the Talkback mic, you would need to make a crosspoint between Mic1 and GxTBack.
The remaining destinations, beginning with Gx In01, represent the channel, or fader,
inputs to the surface. If, for example, Mic2 was the source for channel 4, there would be
a crosspoint connecting Mic2 and Gx In04. This happens whether you take the source at
the surface or go to Xpoint to make the connection

As mentioned above, logic signals are a different breed of animal. When two logic
signals are connected by crosspoint, it is necessary to employ matching function names
to insure that the logic signals interact. The logic function name is chosen in the Signal
Definitions form on the appropriate Tab Logic I/O (1-6) or Logic I/O (7-12). Also, it
is sometimes not immediately obvious whether a logic signal is an input or an output.
Either type of logic signal can be associated with a source or a destination. This can be
very confusing at first. You may have to stop and think about exactly what the logic
function is doing before it becomes apparent as to whether a given signal should be
using the function as an input or an output.

Let's start with the first logic source, GxTIMERS. Looking at the Logic I/O (1-6) Tab,
we see four function names listed: StrtTimr, StpTimr, RstTimr, and HldTimr. These
functions apply to the surface event timer, and can be used to control the timer remotely.
The following screenshot shows the Signal Definitions form for the signal G1TIMERS
with the Logic I/O (1-6) Tab selected

G-4 Auto-Generated Source and Destination Signal Names
There are a few important points to note about this screen before going on. If you are
familiar with the process of setting up logic signals for logic I/O cards, you know that
most logic signals are mapped to such a card. However, these predefined logic signals
are instead mapped to a Mixer Network card, which is a DSP card configured to handle
a surface mix. You're also used to seeing port numbers from 1 to 12, and so the port
numbers of 201, etc., may seem odd. These settings, however, are normal and correct
and should never be changed. The screen is shown here so that you can see the
function names, and the signal direction.

Here's how you would set up a remote switch to activate (start) the surface timer. This
is the only example you'll see in this document, but the principles can be applied to any
system logic interaction. Refer to the Wheatstone BRIDGE Generation Digital Audio
Network System Technical Manual for any details not covered in this discussion. You
will wire the switch to a logic I/O card input port (since you are inputting the switch
action into the system). This is convenient, since logic inputs need to connect to logic
outputs, and the StrtTimr function is defined as an output, as indicated by the Direction
of Out. You will then create a Logic I/O Only destination (because GxTIMERS is a
source) and make a crosspoint connection between the new destination and GxTIMERS.
When defining the logic signal you will use the function name StrtTimr to map the
external switch action to the timer start function. The following screenshots show, first,
the definition of the new logic I/O signal, which has been named MyStart, and next, the
required crosspoint.

G-4 Auto-Generated Source and Destination Signal Names
The next source is GxTALLY. This signal is used to activate ON AIR lights such as
found in Control Room and Studio applications, but with a little creativity can be
applied to other applications, such as controlling a skimmer. There are four logic
signals associated with this source; they are St1InUse, St2InUse, St3InUse, and
St4InUse. These are defined as inputs because they need to connect to logic outputs
which will drive external relays to control air lights, etc.

For the tallies to work as expected, there are VDip settings that need to be made in
Xpoint (this is covered in the main Bridge Router manual). But there is a difference in
the naming convention between VDip and the tally function names. So be aware that
St1InUse corresponds to VDip Studio 1 Tally, St2InUse to Studio 2 Tally, St3InUse
to Headphone Tally, and St4InUse to Control Room Tally.

Next are GxSPAR1 and GxSPAR2. The first of these intefaces with the first 6 of the
surface's programmable buttons, while the second signal covers the remainder of them.
Focusing on GxSPAR1, you will see the switch contacts for programmable buttons 1 – 6
handled on the Logic I/O (1-6) Tab. The function names are Switch1 through Switch6.
These are defined as inputs because, to be useful, they connect to logic I/O card outputs.
On the Logic I/O (7-12) Tab of this signal you find the programmable button LEDs,
with function names of SwLED1 through SwLED6, and defined as outputs. Connect
them to logic I/O card inputs to have remote control of the button LEDs. In the case of
the G-4, which has a total of 8 programmable buttons, GxSPAR2 handles buttons 7 and
8 (although buttons 9 – 12 are defined, they are not used on the G-4).
Before going on to the last signal, a little needs to be said about working with the spare
buttons. There are four modes of operation for the programmable buttons. The default
mode is to have the button act as a momentary switch and to have its LED controlled by
the surface. To change to a different mode, you need to FTP to the surface, using its IP
address. Log on as user knockknock with the password whosthere to view the files
resident on the surface. Locate the file G4_OPTS.TXT and either open it for edit or
drag it to your computer and edit it there in your favorite text editor. With the file open
for edit, scroll down until you see the following block of text:

You can see that the default mode is mode 2. For any given button, change the number
after the ":" from 2 to your choice. When done, make sure the edited file is back on the
surface. You need to reboot the surface for the changes to take effect.
The last source is GxPRESET. This signal is used to enable a surface preset to be fired
from a remote switch. The function names Preset01 through Preset06 appear on the
Logic I/O (1-6) Tab and the names Preset07 through Preset12 appear on the Logic I/O
(7-12) Tab. These are defined as outputs because they need to be connected to logic I/O
card inputs to be useful. The G-4 has only four presets, so the remaining functions are
unused with this surface.

Although there are no destination logic signals, some of the audio destinations (the fader
signals, to be exact) have logic functions associated with them. This section will
describe the functions; they are used in a like manner to functions already discussed.

The Logic I/O (1-6) Tab has the following functions: MachStrt, MachStop, GainCtl1,
GainCtl2, OnTally, and OffTally. All are defined as inputs, meaning they need to be
connected to logic I/O card outputs to be effective. MachStrt and MachStop are
generally used to start and stop remote machines. MachStrt generates a one second
pulse when the channel's ON button is pressed, and MachStop generates a one second
pulse when the channel's OFF button is pressed. OnTally is active while the channel is
on, and OffTally is active while the channel is not on. GainCtl1 and GainCtl2 are
used in conjunction with a channel's gain control; since the G-4 channels do not have
this feature, the two functions are unused with this surface.

The Logic I/O (7-12) Tab contains five additional functions: RemOn, RemOff,
RdyLED, Cough, and Talkback. All are defined as outputs, meaning they need to be
connected to logic I/O card inputs to be effective. RemOn and RemOff are used to turn
the channel on and off, respectively. The RdyLED function is used to flash the
channel's OFF button, and is normally done to indicate a machine is cued up. The
Cough function enables the channel's Cough feature; this acts as a momentary mute so
that talent in the studio can prevent a cough or other extraneous noise from being heard
on air. The Talkback function enables the channel's Talkback feature; this works to put
the channel momentarily in cue to allow the talent to talk to the Control Room operator.

Conclusion
This brief discussion is meant to familiarize the installer or responsible engineer with
the naming scheme used for the surface signals in the Wheatstone Bridge Router system.
This material, used in conjunction with other Wheatstone documentation, will help the
reader to more effectively utilize the features of the surfaces.