User manual POLYCOM EF400

[. . . ] ECHOFREETM EF400 ACOUSTIC ECHO CANCELLER USER MANUAL Copyright © 1999 ASPI Digital. Printed in the United States of America. 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] Remove the adhesive backing on the rubber feet. 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 one EF400 is to be mounted on the shelf, place it in the center. If two units are to be mounted, mount them size by side. If only one EF400 is mounted, attach the two small faceplates supplied with the RS200 to each side of the EF400. Use four more of the small screws to secure the face plates. 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. Such a fall could cause personal injury or equipment failure. 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. Reliable earthing of rack-mounted equipment should be maintained. 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. The red LED should not flicker or illuminate on either meter. [. . . ] Inaccuracies in this decision process can cause another significant problem, one that is handled very elegantly by the EF400. In addition to reducing the effectiveness of the echo cancellation, inaccurate state or mode decisions may introduce artifacts into the transmitted or received speech signals. Words may be clipped or exhibit dropouts. Switch loss or center clipping, which are nonlinear processes, may be applied to a speech signal in the wrong mode. [. . . ]