Vortex EF2241 Reference Manual
VORTEX EF2241 REFERENCE MANUAL Introduction....................................................................................................2 Product Features .................................................................................................... 3 Pre-Installation...............................................................................................5 EF2241 Front and Rear Panels.............................................................................. 6 Installation ..........
INTRODUCTION INTRODUCTION Welcome Congratulations on your purchase of the Vortex EF2241! How to Use This Manual This is a reference manual for your EF2241. It is structured to provide the information you need quickly and conveniently. The following is an overview of each section: • • • • • • • • • • • • About the EF2241 Introduction Pre-Installation includes information about the contents of the box, tools needed for installation and front and rear panel descriptions.
INTRODUCTION busses equals 12 inputs), and 2 mixes of the P Bus for the telephone. The 23 x 17 main matrix has the following outputs: Outputs 1-4 and A-D, AEC Reference 1 and 2, W, X, Y, and Z outputs to the digital expansion bus, P output to the digital expansion bus, output to the power amplifier, and output to the phone line. The EF2241 has 24 bit resolution, 32-bit floating point computation, and a 48 kHz sampling rate.
INTRODUCTION Inputs and Outputs • • • • • 4 microphone/line level inputs with phantom power on each input 24 VDC Phantom Power 4 line level auxiliary inputs with nominal level of 0 dBu 8 line level outputs with default nominal level of 0 dBu Automatic Gain Control (AGC) on Inputs 1-4.
PRE-INSTALLATION PRE-INSTALLATION What’s Included The Vortex EF2241 product package includes the following items: • • • • • • • • • • Vortex EF2241 Reference Manual Vortex EF2241 External power supply Cat 5 cable for EF Bus Telephone cable Rack mount screws (4) Phoenix connectors (16) Cable clamp and screw CDROM containing other manuals and Conference Composer software Product Registration Card Rackmount Screws (4) Vortex® EF2241 x x x Phoenix Connectors (16) x 1-Cat 5 cable for EF Bus Cable Cla
PRE-INSTALLATION EF2241 FRONT AND REAR PANELS 1 2 10 11 12 13 14 3 4 15 5 16 6 7 17 8 9 18 20 19 Figure 2. EF2241 Front and Rear Panels 1. 2. 3. 4. 5. 6. 7. 8. 9. LCD DISPLAY. Displays menu instructions for configuration and operation of the EF2241. DOWN BUTTON. Scrolls backward through menu items at a particular level or decreases the value of a parameter. UP BUTTON. Scrolls forward through menu items at a particular level or increases the value of a parameter. ENTER.
PRE-INSTALLATION 10 11 12 13 14 15 16 Figure 3. Parallel remote control, EF BUS, serial remote control, power supply input, and power amplifier output on back panel of the EF2241. 10. 11. 12. 13. 14. INPUT PARALLEL PORT. Parallel logic input. OUTPUT PARALLEL PORT. Parallel logic output. EF BUS IN. Connects to EF BUS OUT of another Vortex device. EF BUS OUT. Connects to the EF BUS IN of another Vortex device. RS-232 SERIAL PORT.
INSTALLATION INSTALLATION This equipment is intended to only be installed by qualified service personnel. The equipment shall be connected to a socket-outlet that provides a protective earthing connection. North American Requirement CAUTION-To reduce the risk of fire, use only No. 26 AWG or larger telecommunication line cord. MOUNTING THE EF2241 The EF2241 can be mounted in a rack enclosure using four large screws (10-32x1/2”) included with the unit. One EF2241 fits in a single rack space.
INSTALLATION Typical EF2241 Connections The EF2241 will typically be connected to other equipment in a single room setup as shown below in Figure 5 and Figure 6. In 1 Out 1 In 2 Out 2 In 3 Out 3 In 4 Out 4 Polycom Video CODEC In A Out A Line In In B Out B In C Out C In D Line Out Out D Vortex® EF2241 Spk Out Phone Line EFBus In EFBus Out PSTN Figure 5. Block diagram of typical EF2241 connections: a single room using one EF2241.
INSTALLATION • • • • • • Connect speaker output to loudspeaker. If RS-232 remote control is desired, connect the RS-232 REMOTE CONTROL port of the EF2241 to the remote control device, such as an RS-232 interface to a touch panel or a COM port on a personal computer. Connect the LINE RJ11 jack to an analog telephone line. Connect the PHONE RJ11 jack to an analog telephone set (optional). Connect the external power supply to the POWER SUPPLY INPUT jack of the EF2241. Set the country code on the EF2241.
INSTALLATION Terminating the EF2241 The EF2241 is self-terminating so if you are connecting multiple EF2241s, the EF Bus does NOT need to be terminated. However, if you are linking the EF2241 to EF2280s, terminate the EF Bus link. EF Bus Terminator Vortex EF2280 Cat-5 cable ... Cat-5 cable C a t - 5 c a b l Vortex EF2280 e Vortex EF2241 No Terminator Needed Figure 7. Only the EF2280 needs to be terminated when linked together with EF2241s.
INSTALLATION whichever preset you want to come up after power up). The unit will need to be configured for your system.
INSTALLATION PROGRAM PARAMETERS FACTORY DEFAULT PRESET VALUE Input Gains Mic Mode + 15 dB = 48 dB for Inputs 1-4 0 dB for Inputs A-D Manual Threshold 60 dB Mute Off Noise Cancellation On Noise Cancellation Level 10 dB Phantom Power On OUTPUT CHANNELS Presets and Multiple Vortex Devices Mute Off NOM Attenuation On for Outputs 1-4 On for Outputs A-D Output Gain 0 dB PRESET 0 is preconfigured for a system with multiple Vortex devices.
INSTALLATION Configure the matrix mixer input from the codec output. The input gain of the matrix mixer should be set to match the nominal output level of the codec. For example, if the codec outputs a -10 dBV (-8 dBu) level, 8 dB of gain should be applied on the matrix mixer input. This will bring the codec level up to 0 dBu inside the matrix.
INTEGRATING THE EF2241 INTO YOUR SYSTEM INTEGRATING THE EF2241 INTO YOUR SYSTEM Operating the EF2241 The EF2241 can be operated in two ways: through the LCD menu on the front panel or through RS-232. For control via RS-232, please refer to the EF2241 Programming Guide, which includes programming tips as well as the EF2241 RS-232 commands. For operation using the PC control software, Conference Composer, please refer to the Conference Composer User Guide.
INTEGRATING THE EF2241 INTO YOUR SYSTEM you should increase your input gain by 15 dB. If the meter shows an average gain of +10 dB, you should decrease your input gain by 10 dB. AGC Level Meter Read AGC level Adjust Input Gain here Figure 9. AGC Meter on the Diagnostics page of the Conference Composer software. The gain adjustment is the same gain control on the Mic/Line Inputs page in Conference Composer. IF THE AGC METER SHOWS... ADJUST THE INPUT GAIN IN THIS WAY.
INTEGRATING Customize Setting for Your Particular Application THE EF2241 INTO YOUR SYSTEM The following sections will describe customizing parameters on the EF2241 for your particular application if you are not using Preset 0. SET UP THE PHONE INTERFACE The echo canceller reference of the EF2241 is by default set up with the phone input already assigned to it. By default the phone interface will be disabled until you select a country code for the telephony interface.
INTEGRATING THE EF2241 INTO YOUR SYSTEM for their echo canceller, or they can use their own internal references. The references may include a mix of any input, with crosspoint gains, including W, X, Y, and Z busses. Set the EF Bus Reference in the System Menu of the LCD Menu (See “EF Bus Reference” on page 28). Setting up the Bus Reference If all far end audio and program audio sources are on the same Vortex device, 1. 2. 3.
INTEGRATING THE EF2241 INTO YOUR SYSTEM Figure 12. Matrix page of linked devices If far end audio and program audio sources are on several Vortex devices. 1. 2. Bus each far end audio and program audio source to each device. Do this by assigning each signal input to either the W, X, Y or Z bus. Assign an echo canceller reference on each device that will include all far end audio and program audio sources.
INTEGRATING THE EF2241 INTO YOUR SYSTEM Local Max NOM, Global Max NOM, Off Attenuation, Threshold Type, Gating Mode, Adaptive Threshold, Manual Threshold, and Gate Priority. Signal Level Channel turns on when signal level is above Adaptive Threshold DECAY TIME Channel ON ADAPTIVE THRESHOLD Channel OFF Microphone Audio HOLD TIME OFF ATTENUATION Ambient Level Time Figure 13. Off Attenuation, Hold Time, Adaptive Threshold, and Decay Time. Global Settings. Decay Time.
INTEGRATING THE EF2241 INTO YOUR SYSTEM (NOM) limit for each linked automixer. The maximum value for this command is 64. This NOM limit is a “global” limit, meaning that this limit applies to all linked automixers with the same Bus ID. Off Attenuation. Sets the Off Attenuation (in dB) for the specified automixer. Setting this value to 18 would result in the microphone signals being attenuated by 18 dB when gated off. This value is set independently for each of the automixers. Channel Settings.
INTEGRATING Automixer and Bus Mixer Settings THE EF2241 INTO YOUR SYSTEM To operate the Vortex device in any of the above possibilites, two global parameters need to be changed: the AUTOMIXER and the BUS MIXER (see Figure 14). The AUTOMIXER parameter chooses which automixer the input channel will be on (this is changed either on the AUTOMIXER page in Conference Composer or on the MATRIX MIXER page).
INTEGRATING THE EF2241 INTO YOUR SYSTEM 1. Assign Inputs Assign each audio source to an input. Remember to include the conferencing equipment such as a video codec and any program audio. 2. Assign Outputs Try to assign as many outputs as you can to one Vortex device to make a simpler submatrix. Remember that Outputs 1-4 can also be used as outputs of the matrix. The bussing gets more complicated if you choose to spread your outputs over several units. 3. Configure the submatrix.
THE EF BUS THE EF BUS The EF Bus is a high speed, low delay digital bus that includes the W, X, Y, and Z audio busses, the P bus, as well as the echo canceller bus reference and remote control information (for other EF devices). It can link up to 8 Vortex devices. The W, X, Y, and Z busses include NOM information and can be used for sharing microphone inputs, or for sharing mono or stereo program information.
THE EF BUS EF Bus Reference. In a system with multiple devices, if all devices need the same echo canceller reference, one device should be designated to put its echo canceller reference (either Ref 1 or Ref 2) on the EF bus to be used as the EF Bus Reference. All other devices may use the EF bus reference as the reference for their echo cancellers, or they can use their own internal references. The references may include a mix of any input, with crosspoint gains, including W, X, Y, and Z busses. NOM Bus.
LCD MENU STRUCTURE LCD MENU STRUCTURE LCD Menu Tree The EF2241 LCD menu structure is made up of nine menu trees: SYSTEM, PHONE CONTROL, INPUTS, OUTPUTS, AUTOMIXER, MATRIX, PARAMETRIC EQ, PRESETS, and MACROS. Each menu tree is organized by levels and branches into multiple subcategories. The branches end with an adjustable parameter or value.
LCD MENU STRUCTURE must be flashing. To make the parameter flash (assuming the front panel is not locked) press ENTER. Once the parameter is flashing, use the UP and DOWN buttons to adjust the parameter value. The parameter is instantly updated while it is being adjusted — you should hear changes as the parameter is changing. RS-232 control strings are also sent via the RS-232 port so your remote control device is instantaneously updated as well.
LCD MENU STRUCTURE SYSTEM MENU System Power On Preset Acknowledgement Mode The SYSTEM menu contains POWER ON PRESET, ACKNOWLEDGEMENT MODE, BUS REFERENCE, ERROR MESSAGES, FRONT PANEL LOCK, FRONT PANEL PASSWORD, DEVICE ID, BAUD RATE, FLOW CONTROL, LCD CONTRAST, METER, NON-VOLATILE MEMORY LOCK, NON-VOLATILE MEMORY PASSWORD, SCREEN SAVER, SOFTWARE VERSION, and REBOOT EF2241 configurations. Power On Preset. Choose the EF2241 Preset for power up. Acknowledgement Mode.
LCD MENU STRUCTURE PHONE CONTROL Auto Answer. Enables or disables auto answer. Auto Hangup Call Progress. Enables or disables auto hangup based on call progress messages. Phone Control Auto Answer Auto Hangup Call Progress Auto Hangup Loop Drop Country Select Dial Tone Gain Auto Hangup Loop Drop. Enables or disables auto hangup cased on loop drop. Country Select. Selects the country where you are using the unit.
LCD MENU STRUCTURE INPUTS Inputs 1-4, T, A-D Acoustic Echo Cancellation (In 1-4) Automatic Gain Control (AGC), In 1-4, T AGC Maximum (In 1-4, T) AGC Minimum (In 1-4, T) Gain Level Mic/Line (In 1-4) Mute Noise Cancellation (In 1-4, T) Noise Cancellation Level (In 1-4, T) Phantom Power (In 1-4) Reference Assign (In 1-4) AEC Suppression (In 1-4) Line Echo Cancellation (In T) The input menu allows the user to adjust functions related to the input signals to the EF2241.
LCD MENU STRUCTURE Phone Input Gain. This parameter adjusts the gain level of the Phone input. Phone AGC. Enables or disables automatic gain control on the Phone. OUTPUTS The OUTPUT menu contains GAIN, NOM ACTIVE, and MUTE. As with the INPUT menus, this is done on a per channel basis. Outputs Output Gain Mute Output NOM Attenuation On/Off Output Delay Enable Output Delay Dynamics Processing Output Gain. Choose the gain applied to each output signal using this parameter. The default setting is 0 dBu.
LCD MENU STRUCTURE THRESHOLD, MANUAL THRESHOLD, and GATE PRIORITY. Signal Level Channel turns on when signal level is above Adaptive Threshold DECAY TIME Channel ON ADAPTIVE THRESHOLD Channel OFF Microphone Audio HOLD TIME OFF ATTENUATION Ambient Level Time Figure 22. Automixer parameters. Global Settings. Automixer Global Settings Decay Hold Time Camera Gating Threshold Decay Time.
LCD MENU STRUCTURE Mixer Settings. Automixer Mixer Settings (AM1/AM2) Bus ID Chairman Mode Chairman Mic Last Mic On Mode Last Mic Number Local Max NOM Global Max NOM Off Attenuation Automixer Reference Reference Bias Bus Mixer. This command is used to assign one of the two internal automixers to one of the EF Bus automixer groups. For example, consider three Vortex devices each of which has 2 microphones assigned to Automixer 1 and 2 microphones assigned to Automixer 2.
LCD MENU STRUCTURE Gate Priority. The priority of each microphone can be assigned a value ranging from 1 to 4. Priority 1 microphones have priority over priority 4 microphones for gating. The default is to have all microphones set to priority 1. If Chairman Mode is enabled, all microphones including ones with priority of 1 will be gated off when the Chairman mic gates on.
LCD MENU STRUCTURE PARAMETRIC EQ MENU The input equalizer is comprised of up to 5 bands of filtering. The whole group of filters for the channel can also be enabled/disabled without losing the settings for each band. For each band, you first select the type of filter from the following: Parametric/ Peaking, High Shelf, Low Shelf, Lowpass, or Highpass. Parametric EQ Input/Output EQ Channel Band Filter Type Frequency Bandwidth Gain Slope Filter Enable Figure 24.
LCD MENU STRUCTURE PRESETS Restore. Restores the selected preset. Save. Saves the selected user preset (Presets 16-47). Factory presets (Preset 0-15) cannot be overwritten. Presets Restore Delete. Deletes the selected user preset (Presets 16-47). Factory Presets (Presets 015) cannot be deleted. Save Presets 16-47 Delete Presets 16-47 Figure 25. EF2241 Presets submenu MACROS Run Macro (0-255). Allows you to run macros from the front panel menu. Macros Run Macro (0-255) Figure 26.
TROUBLESHOOTING TROUBLESHOOTING AUTOMATIC MICROPHONE MIXER No microphones are gating • • Check if the microphones are muted. Are microphones part of one of the 2 automixers? Some microphones are not gating • • • Check if the microphones are assigned to an automixer. Check if the microphones are muted. Check microphone levels. Are microphones set to the appropriate mic or line level? Is phantom power on where needed? The Hold Time may be too low.
TROUBLESHOOTING MATRIX MIXER Don’t hear output • • Make sure the output is not muted. Check that the input you’re expecting to hear is included in the output that you’re listening to. ECHO CANCELLER REFERENCE Room Audio Sounds Choppy If you hear the local room’s audio from the loudspeakers and it sounds choppy, you may have included the room’s microphones in the echo canceller reference.
TROUBLESHOOTING AEC Reverberation Acoustic Echo Figure 27. Reverberation vs. Acoustic Echo. Reverberation is not an artifact of the echo canceller. It is mainly affected by the distance of the microphone from the speech source and by the resonances of the room. While reverberation can be unpleasant, it is not compensated for by the acoustic echo canceller (AEC), which only removes reflections of remote speech.
TROUBLESHOOTING and the level of this signal that is reflected as the microphone input (after microphone amplification). A AEC B Room Gain = 20 log (B/A) Figure 28. Room Gain. If the electrical level of the reflected signal picked up by microphone is the same as the level of the electrical signal sent from the AEC to the loudspeaker output, the room gain of this microphone channel is said to be 0 dB.
TROUBLESHOOTING talker to the microphone. The microphone audio will most likely also be muddy and reverberant. The installer or user may try to solve these microphone audio quality problems by turning up the microphone amplification, thus adding to the room gain. This problem can be remedied by proper microphone selection (pickup pattern, directionality) and placement, coupled with proper microphone input calibration. 3.
TROUBLESHOOTING Nonlinear distortion causes a degradation or divergence of the AEC’s internal model of the room acoustics. In this situation, the EF2241 cannot effectively cancel room echoes and a substantial amount of echo may be heard by the remote party. Excessive microphone amplification also increases room gain (See “Excessive Room Gain” on page 40.). You can check for excessive microphone amplification by observing the front panel LEVEL INDICATOR during a normal conference.
TROUBLESHOOTING If you suspect the loudspeaker is introducing nonlinearities into the room acoustic path, take these steps to minimize its influence on the echo canceller. • • • Keep the loudspeaker’s volume level at less than three-eighths of full scale. If higher volume is required, the EF2241 should operate effectively at volume settings of up to 50 percent of full scale. At more than 50 percent, most audio systems and loudspeakers introduce significant nonlinearities.
TECHNICAL SPECIFICATIONS TECHNICAL SPECIFICATIONS MECHANICAL SPECIFICATIONS Dimensions 19” (483 mm) W x 9.6” (244 mm) L x 1.75” (45 mm) H (full rack unit) Weight 4 lb. (1.8 kg) dry 5.5 lb. (2.5 kg) shipping Connectors Audio: Mini (3.
TECHNICAL SPECIFICATIONS COMPLIANCE The Vortex EF2241 complies with the ITU G.167 Recommendation for AEC, FCC part 15, and CE requirements. USA and Canada This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: 1. 2. NOTE This device may not cause harmful interference, and This device must accept any interference received, including interference that may cause undesired operation.
TECHNICAL SPECIFICATIONS • • If, in the unlikely event that this equipment causes harm to the network, the telephone company will notify you in advance that temporary discontinuance of service may be required. But if advance notice isn't practical, the telephone company will notify you as soon as possible. Also, you will be advised of your right to file a complaint with the FCC if you believe it necessary.
TECHNICAL SPECIFICATIONS NOTICE: The Ringer Equivalence Number (REN) assigned to each relevant terminal device provides an indication of the maximum number of terminals allowed to be connected to a telephone interface. The termination on an interface may consist of any combination of devices subject only to the requirement that the sum of the Ringer Equivalence Numbers of all the devices does not exceed 5.
TECHNICAL SPECIFICATIONS This page was intentionally left blank. VORTEX EF2241 Reference Manual 48 Technical Support: 800.932.
CE Mark R& TTE Directive This EF2241 has been marked with the CE mark. This mark indicates compliance with EEC Directives 89/336/EEC, 73/23/EEC 1999/5/EC. A full copy of the Declaration of Conformity can be obtained from Polycom Ltd, 270 Bath Road, Slough, Berkshire, SL1 4DX, UK. Declaration of Conformity: Hereby, Polycom Ltd. declares that this EF2241 is in compliance with the essential requirements and other relevant provisions of Directive 1999/5/EC. Konformitetserklæring: Hermed erklærer Polycom Ltd.
Polycom Ltd. förklarar härmed att denna EF2241 överensstämmer med de väsentliga kraven och övriga relevanta stadganden i direktiv 1999/5/EG. VORTEX EF2241 Reference Manual 48 Technical Support: 800.932.
CONFERENCE SYSTEM DESIGN CONFERENCE SYSTEM DESIGN Good audio or video conferencing is more than acoustic echo cancellation. Before installing the EF2241, you should consider how your whole conference system will work together.
VORTEX EF2241 Reference Manual 50 + Mic/Line Phantom + - Level adjust Mic/Line + - A/D EN PEQ Level adjust Phantom D/A + - Delay Line Output 4 R1, R2, Bus Echo Canceller On Off Noise Canceller On Off AGC EN (Echo Canceller, Noise Canceller) Mic/Line 2 Mic/Line 3 Mic/Line 4 Mic/Line Mic/Line 1 Phantom Mic/Line + - Phantom Level adjust A/D A/D A/D Level adjust EN EN PEQ PEQ PEQ EN Delay + - Delay Line Delay + - D/A Line Output 3 D/A + - Output 2 D/A Lin
CONNECTOR PINOUTS CONNECTOR PINOUTS EF Bus EF BUS IN 8 1 1 8 The EF Bus uses RJ45 connectors. These should be used with category five twisted-pair cable. The total distance of the EF Bus should be less than 4.5 m. The EF Bus must be connected so that the EF Bus In of one box is connected to the EF Bus Out of another. Connecting the EF Bus In to another EF Bus In (or Out to Out) will not work.
CONNECTOR PINOUTS Input/Output Remote Control Port INPUT 13 Logic Input: Pins 1-24 are inputs 1-24, respectively. Pin 25 is ground. 1 25 14 REMOTE CONTROL Logic Output: Pins 1-20 are outputs 1-20, respectively. Pins 21-25 are ground. Each ground pin should be used with only 4 outputs. For example, outputs 1-4 could be connected to LEDs, which are connected to ground pin 1. OUTPUT LEDs can be used without series resistors (we have provided series resistors in the circuitry).
CONNECTOR PINOUTS CONNECTING UNBALANCED RCA TO BALANCED MINI PHOENIX RCA Male Mini (3.5 mm) Phoenix Tip Red Black Red + 1 Black - 2 Shield 3 Ring Figure 31. Cable construction for connecting unbalanced RCA to balanced mini Phoenix (3 conductor terminal block). 1. 2. 3. Connect RCA Tip to Phoenix pin 1. Connect RCA Ring to Phoenix pin 2. Connect Phoenix pin 3 to Shield, and leave Shield floating on RCA end. Caution! Do NOT connect the shield at both ends.
CONNECTOR PINOUTS ADDITIONAL NOTES Caution! Caution! Caution! Caution! Caution! Failure to use all four screws to attach the EF2241 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 a EF2241 in a rack, consideration should be given to airflow and operating ambient temperatures inside the rack.
WARRANTY INFORMATION WARRANTY INFORMATION What is covered Any defect in materials or workmanship. For how long Two years. What we will do If your Vortex EF2241 product is defective and returned within two years of the date of purchase, we will repair or, at our option, replace it at no charge to you. If we repair your Vortex product, we may use new or reconditioned replacement parts.
WARRANTY INFORMATION What this warranty does not cover This warranty does not cover defects resulting from accidents, damage while in transit to our service location, alterations, unauthorized repair, failure to follow instructions, misuse, fire, flood, lightning, acts of God, or use in those countries where such use violates Part 779 of the Export Administration Regulations of the United States Department of Commerce.
DEFINITION OF TERMS DEFINITION OF TERMS Acoustic Echo Acoustic echo occurs in a conferencing or distance learning system when the remote speech played in the loudspeakers is picked up by microphones in the room and is transmitted back to the remote end. This transmitted signal is a delayed version of the original, which causes the echo. Acoustic Gain Acoustic gain is a term used in conjunction with sound reinforcement.
DEFINITION OF TERMS EF Bus The EF Bus is a digital bus that includes the W, X, Y, and Z audio busses as well as the echo canceller reference and remote control information. It can be used to link multiple Vortex devices. Equalization Equalization is the process of adjusting frequency characteristics of an audio signal. Line Echo Line echo is caused by reflections of the audio signal from the telephone hybrid. The EF2241 is an example of a device that includes a line echo canceller.
DEFINITION OF TERMS room gain of this microphone channel is said to be 0 dB. If the reflected signal picked up by the microphone is higher than the level of the signal sent to the line output to your amplifier, that microphone channel has positive room gain. The more positive the room gain, the harder the AEC must work to determine which signal is an echo and which is a local speech signal. © Polycom, Inc.
INDEX INDEX A B C D E Acoustic Echo Cancellation, AEC ........................................................2, 12, 17, 30, 38, 40, .................................................................................................................44, 49, 57 Automatic Gain Control (AGC) ............................................................4, 30, 57 Automixer, Adaptive Threshold ..........................................................12, 21, 33 Automixer, Adaptvie Threshold ......................
INDEX F G I L M N O P Factory Default Settings, Preset 0 .....................................................11, 13, 15, 22 Front Panel Lock ...................................................................................28 Ground ....................................................................................................52 Ground, Chassis ....................................................................................53 Ground, Logic Input .............................................
INDEX .................................................................................................................58 Power Amplifier .....................................................................................2, 3, 7, 44 Power On Preset ...................................................................................13, 25 Presets ....................................................................................................58 R S T V Reference, AEC .................................
Polycom, Inc. Installed Voice Business Group 1720 Peachtree Street NW, Suite 220 Atlanta, GA 30309-2439 Phone: (800) 932-2774, (404) 892-3200 Fax: (404) 892-2512 www.polycom.com Technical Support: (800) 932-2774 vortex@polycom.com Polycom®, Vortex®, and the Polycom logo are registered trademarks of Polycom, Inc. in the United States and various countries. Copyright © 2002 Polycom, Inc. All rights reserved.
