Polycom Vortex EF2241 Programming Manual page 14

The EF2241 has eight analog outputs labeled 1-4 and A-D. These outputs are all at line level. There are two
additional outputs: the output to the telephone interface, labeled T, and the output to the power amplifier,
labeled L (for loudspeaker). This yields a total of ten physical outputs.
The EF2241 has eight analog inputs labeled 1-4 and A-D. Inputs 1-4 are mic/line selectable, and inputs A-D
are line level only. Inputs 1-4 can also have phantom power enabled and contain channel processing, which
includes the following DSP algorithms: Acoustic Echo Cancellation, Noise Cancellation, AGC, and Automatic
Microphone Mixing. An additional input, labeled T, comes from the telephone interface. The T input also has
signal processing which includes the following algorithms: Line Echo Cancellation, Noise Cancellation, and
AGC. Inputs 1-4, A-D, and T yield a total of 9 physical inputs.
Vortex devices can be linked together so that they can share control information and digital audio signals.
The audio signals are shared on four digital busses labeled P, W, X, Y, and Z. All Vortex devices can receive
signals from all of these busses. Only certain devices can transmit on the busses. This information is given in
the following table.
Device Transmit on P Bus
EF2280 No
EF2241 Yes
EF2211 Yes
EF2210 No
EF2201 Yes
The P bus is meant for routing telephone audio between the devices. The W, X, Y, and Z busses are meant
for routing microphone and auxiliary audio between the devices. The W, X, Y, and Z busses also carry NOM
(Number of Open Microphones) information from the automixer so that outputs created from these busses
can be appropriately attenuated for the number of open microphones.
The digital inputs consist of all of the signals placed on the EF Bus by the other connected Vortex devices.
Each P, W, X, Y, and Z bus can carry channels from up to eight other devices, so we have the following
digital inputs to each Vortex device: PB0-PB7, WB0-WB7, XB0-XB7, YB0-YB7, and ZB0-ZB7. The inputs are
designated by three characters: the bus letter (P, W, X, Y, or Z), a B indicating that it is a bus input, and a
number between 0 and 7 indicating the channel of the bus.
There is also an internal signal generator, labeled SG, that is capable of producing white or pink noise. this
signal is fed into the matrix so that it can be routed to the appropriate outputs for calibration or testing.
The mixing capabilities of the Vortex devices can be broken down into two parts: the EF Bus submatrices and
the main matrix.
For each of the W, X, Y, and Z signal busses, there is a 7 x 3 matrix that allows the user to define up to
three mixes of each of the four signal busses. The reason the matrix is 7 x 3 instead of 8 x 3 is that since we
can transmit on the W, X, Y, and Z busses, we do not need to mix our own channels in these matrices. The
inputs and outputs for the 7 x 3 matrices are as follows.
Transmit on W, X, Y, Z
Busses
Yes
Yes
Yes
Yes
No
Receive W, X, Y, Z
Receive P Bus
Busses
Yes Yes
Yes Yes
Yes Yes
Yes Yes
Yes Yes