User manual POLYCOM EF2280

[. . . ] Interfacing Vortex® Devices to Video Codecs Application Note Polycom Installed Voice Business Group Revision I September 2004 Table of Contents TABLE OF CONTENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 TABLE OF CONTENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ® TM POLYCOM IPOWER 600 SERIES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Connecting the iPower 600 Series Inputs and Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] This is important to note because if the volume control is very low, it may appear that the codec audio is operating correctly because the sound effects are still generated and will be heard in the local room. However, when a call is connected, the local side may not hear the far side because the local volume control is too low. Since the local participants heard the sound effects audio at a normal level, it may not be obvious that the volume control is set too low. 36 The sound effects volume control can be adjusted in the System Info, Admin Setup, Phone Audio page. If the ViewStation EX is turned off either through the power switch or unplugged from the wall while the codec is still connected to the Vortex device via the input and output audio cables, a loopback will occur in the codec. This means that a portion of the audio signal that is sent to the codec from the Vortex device will be coupled into the signal that is sent from the codec to the Vortex device. This will cause the local room to hear a reinforced version of their own speech via the local room loudspeakers. Our recommendation is to leave the codec power on all the time; however, if the codec must be powered down, we recommend muting either the output channel of the Vortex device that will feed the input of the codec or the input channel of the Vortex device that is connected to the output of the codec. Polycom ViewStation FX CONNECTING THE VIEWSTATION FX INPUTS AND OUTPUTS In order to send and receive audio to the Polycom ViewStation FX codec, you need to observe the following procedure: 1. Connect one of the Outputs of the Vortex device to the mixer input of the codec. By default, Outputs A-C of the Vortex device are mix-minus versions of the Inputs A-C signals. Connect the auxiliary line level output of the codec to one of the line level inputs of the Vortex device (Inputs A-D). You may use one of the Mic/Line level inputs, but you need to disable all processing on that input (AEC, AGC, NC, Automixer), disable Phantom Power, and set the input to line level versus the default of mic level. Follow the diagram below to make the proper physical connections to the codec. Do not use any other audio inputs or outputs as they could cause an audio loopback to occur within the codec. 37 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 FX to Vortex device"). Failure to do so may induce noise into the signals sent and received from the codec. 38 3. Raise the gain on the appropriate Input of the Vortex device to +10 dB. 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. SETTING THE AEC REFERENCE USING A VIEWSTATION FX 1. [. . . ] For simplicity, you may round that value 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. The outputs W and Y are signals that will be sent over the EFBus to the EF2201. See the section entitled Conference Composer Layout EF2201 to find out how to take those signals from the bus and send the to the telephone line. [. . . ]