Polycom EF2201 Brochure & Specs page 43

Program L signal (the left channel of the
program audio), and output Z is the Program R
signal (the right channel of the program audio).
That's all there is to do to put signals on the
expansion bus. The W, X, Y, and Z signals
from EF2280:00 can now be used by other
linked Vortex devices.
Expansion Inputs Example
Now, let's look at it how another Vortex device
can read these bus signals and use them
locally. Let's assume that Vortex EF2280:04
wants to use the microphone signals that
Vortex EF2280:00 has put on the W bus. How
does it do that? When a Vortex device wants
to use signals that are on the bus, it can create
sums of the bus signals that can be used in its
main matrix. The bus signals from other
Vortex devices are summed together (with
arbitrary gains) to create the combination
signals WM0, WM1, WM2, XM0, ... as
shown in Figure 19. These combination signals
can then be used in the main matrix and used
as any other input to the matrix as shown in
Figure 20. In Figure 19, WM0 is a user defined
summation of the W signals that have been
placed on the W bus by the other Vortex
devices and can contain any combination of W
signals (with the exception of a Vortex's own
W bus signal) that are on the bus. In this
figure we can also see that WM1 and WM2
only contain muted inputs from the bus (the
light gray crosspoints indicate the signals are
muted). By having Vortex EF2280:00 output
the sum of its microphones to the W bus (this
is done in the main matrix for the EF2280:00),
Vortex EF2280:04 can pull the EF2280:00 W signal off the bus and create a mix on outputs WM0, WM1, or WM2 – three different
combinations of signals from the W bus can be created. To do this, the user would go to the EF Bus page on Vortex EF2280:04 and
unmute the WB0 signal (the W signal from Vortex EF2280:00) in the row that is summed together to form WM0 as shown in Figure
19. Just as the WM0 signal is a combination of signals from the W bus, the EF2280:04 bus combination signal XM0 is a user
defined combination of all the X bus signals that the other devices (except Vortex EF2280:04 in this case) put onto the expansion
bus and so forth for the other bus signals YM0, ..., YM2, ZM0, ..., and ZM2. The next section provides an example of using these
signals.
I
Figure 19. A screen shot of the bus mixer for Vortex EF2280:04 showing the sub matrix
associated with the EF Bus. Notice that column 4 is grayed out – EF2280:04 cannot use as
input signals the output signals that it put on the bus. The highlighted row shows the sum of
all the W signals from other linked Vortex devices being summed together to create the
signal WM0.
Figure 20. A screen shot of the matrix for EF2280:04 showing that EF2280:04 is using the
bus input signals with the PM0 bus combination is sent to output 3, the WM0 bus
combination is sent to output C, the Y bus combination is to outputs 1 and C (with 3dB of
attenuation), and the Z bus combination is going to outputs 2 and C (with 3 dB of
attenuation).
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