Setting The Aec Reference Using A Viewstation 128 / H.323 / Mp / 512 - Polycom Vortex EF2241 Application Note

You may connect either the left or the right channel of the auxiliary line level output to
the Vortex device. Any audio that is sent from the far side will be monaural.
Please follow our instructions for wiring the Vortex device to the codec (See "Wiring
from ViewStation 128/H.323/MP/512 to Vortex device"). Failure to do so may induce
noise into the signals sent and received from the codec.
3. Raise the gain on the appropriate Input of the Vortex device to +10 dB.
4. Lower the gain on the appropriate Output of the Vortex device to -10 dB.
It is important to set the gain structure correctly so that you don't clip the input audio
stage of the codec and that the Vortex device gets a good signal to perform processing
with. The nominal input and output of the codec is .3 V rms. The nominal input and
output of the Vortex device is .775 V rms. This equates to a difference of 8.24 dB between
the two nominal levels. For simplicity, you may round that value to 10 dB.
S
ETTING THE
128 / H.323 / MP / 512
1. Connect a monitor to Output 1 of the codec. By default, the composite output is enabled and the S-
Video output is disabled.
2. Go to S
I
YSTEM NFO
warning that is displayed on the screen about disabling the echo canceller and select OK.
3. Once that is completed, make sure that the Input to the Vortex device is assigned to the
appropriate AEC Reference signal. Consult Reference Manual for the Vortex device or the Help file
in Conference Composer for more information.
AEC R
EFERENCE
, A S , P A
DMIN ETUP HONE UDIO
U V
SING A
, and check the E C
CHO ANCELLER
S
IEW TATION
option. Ignore the
30