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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] Consult Reference Manual for the Vortex device or the Help file in Conference Composer for more information. TESTING THE AUDIO INPUTS AND OUTPUTS 2. Go to SYSTEM INFO, ADMIN SETUP, PHONE AUDIO, and check the ECHO CANCELLER option. You must enable the codec's internal echo canceller in order for the audio meter described in Step 2 to work properly. Go to SYSTEM INFO, DIAGNOSTICS, AUDIO, AUDIO METER and then speak into one of the microphones. You may also use the loop-back feature to listen to your own audio in the local room. Go to SYSTEM INFO, DIAGNOSTICS, AUDIO, GENERATE TONE to listen to a codec-generated 1 kHz tone. Go to SYSTEM INFO, ADMIN SETUP, PHONE AUDIO, and un-check the ECHO CANCELLER option. 35 WIRING FROM VIEWSTATION EX TO VORTEX DEVICE The inputs and outputs to most codecs are unbalanced. We recommend keeping the cable from the Vortex device as short as possible to avoid any common-mode signals that may corrupt the audio. INPUT TO VIEWSTATION EX FROM OUTPUT OF VORTEX DEVICE Connect the Positive conductor of the Vortex device to the Tip of the RCA connector and the Negative conductor of the Vortex device to Shield of the RCA connector. The shield of the cable is not connected. OUTPUT OF VIEWSTATION EX TO INPUT OF VORTEX DEVICE Connect the Positive conductor of the Vortex device to the Tip of the RCA connector and the Negative conductor of the Vortex device to Shield of the RCA connector. The shield of the cable is not connected. TIPS FOR VIEWSTATION EX 1. The volume control for the ViewStation EX controls the incoming far side audio and the local tone generator. It does not, however, control the sound effects inside the units such as incoming call ring and the female speech that occurs when you dial a number. 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. [. . . ] Inputs B and C are reduced by 10 dB to Output Y because if a program source is mixed at 0 dB with local speech, it may be difficult for the remote person on the telephone to distinguish between the program audio and the local speech because of the frequency limitations of the telephone network. By attenuating the program audio, you "bias" the audio sent to the telephone in favor of the local speech. The reason is that the nominal input and output of the codec is . 3 V rms. This equates to a difference of 8. 24 dB between the two nominal levels. [. . . ]