User manual POLYCOM EF400

[. . . ] ECHOFREETM EF400 ACOUSTIC ECHO CANCELLER USER MANUAL Copyright © 1999 ASPI Digital. Because of technical progress, specifications are subject to change without notice. EchoFree is a trademark and ASPI is a registered trademark of ASPI Digital. ASPI Digital - The Sound of DSP 1720 Peachtree Street NW, Suite 220 Atlanta, GA 30309-2439 (404) 892-3200 www. echofree. com Technical Support: (404) 892-3200 help@aspi. com EF400UM-0100-99 EF400 USER MANUAL Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Product Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Preparing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] The EF400 is now ready for tabletop or rackmount installation. SCREWDRIVER Tabletop Installation The EF400 is equipped with four rubber feet that allow installation on a flat surface such as a tabletop. Install the rubber feet in the circular cutouts on the EF400 baseplate. Rackmount Installation 1. After you complete the configuration and calibration procedures, place the EF400 on the ASPI Digital RS200 Shelf. Secure the EF400 to the RS200 shelf using four of the small screws (4-40 x ¼") provided with the RS200. If only one EF400 is mounted, attach the two small faceplates supplied with the RS200 to each side of the EF400. Secure the RS200 shelf to the rack using all four large screws (10-32 x ½") supplied with the RS200. The EF400 power supply block should be placed securely in the base of the rack unit. To eliminate any risk of the power cable being pulled out of the EF400 rear panel connector, use the plastic Ty-Wraps provided with the RS200 to provide strain relief by securing the power cable to the rack upright at the rear of the EF400. 3. 4. 5. Caution! Failure to use all four screws to attach the RS200 shelf to the rack may result in uneven loading and cause a safety hazard. Ensure that the power supply is securely located such that it cannot become dislodged and fall. When mounting an EF400 in a rack, consideration should be given to airflow and operating ambient temperatures inside the rack. To ensure safe operation of the EF400, ambient operating temperatures inside the rack should not exceed 50 degrees Celsius. Allow 2 inches of open space in front of the EF400, and four inches behind the unit for proper ventilation. Equipment should not be installed in the rack in such a way as to interfere with ventilation to the EF400. Caution! Caution! ASPI Digital - The Sound of DSP 15 EF400 USER MANUAL Caution! Consideration should be given to the connection of the equipment to the supply circuit and the effect that overloading of circuits could have on overcurrent protection and supply wiring. Appropriate consideration of equipment nameplate ratings should be used when addressing this concern. Particular attention should be given to supply connections other than direct connection to the Branch (use of power strips). Caution! CALIBRATION VERIFICATION During normal operation (a conference), observe the front panel MICROPHONE INPUT LEVEL INDICATOR and REMOTE INPUT LEVEL INDICATOR. If either red LED illuminates or flickers frequently, reduce the corresponding input level. The calibration process accommodates a nominal speech level at the room microphone (normal speech at 1m to 2m from the microphone). During normal speech in a conference, the first yellow LED should illuminate frequently, and the second yellow LED should flicker regularly during periods of louder speech. Extreme and unusual levels (for example, a participant shouting into the microphone) may overdrive the input level and cause the red LED to illuminate. This is not cause for concern unless you expect this condition to be the normal operating mode!Similar speech activity levels at the local and remote ends should cause the same number of LEDs to illuminate on both signal strength meters. [. . . ] Such changes occur when volume levels are changed; people move about; doors are opened or closed; the loudspeaker or the microphone is moved; and so on. Adaptation should only occur when in receive mode (for example, when the local party is silent and the remote party is talking). Inaccurate mode decisions cause the AEC's internal model to diverge and echoes are not effectively canceled. Inaccuracies in this decision process can cause another significant problem, one that is handled very elegantly by the EF400. [. . . ]