Polycom Vortex EF2280

Acoustic echo/noise canceller with automatic microphone/matrix mixer
Benefits Industry leading audio quality Design enhancements improve the audio experience for even the most demanding listening environments; support for the broadest range of microphones in the industry Hear every word with Polycoms industry-leading acoustic echo and noise cancellation Ensures the highest possible audio quality between sites with 20 kHz bandwidth, 270 ms tail length, more than 10 dB of room gain, and a convergence rate of over 40 dB per second on each mic/line channel Integrated voice and video solution May be linked with additional Vortex Installed Voice products including Vortex EF2201, Vortex EF2210, Vortex EF2211, the Vortex EF2241 and Vortex EF2280; Polycoms SoundStation VTX 1000 wideband conference phone and Polycoms video conferencing systems including the VSX 7000 and 8000 product lines Easy setup Conference Composer and Polycom InstantDesigner software make configuration fast and simple Easy to operate Controllable via Crestron, AMX or other room control systems, RS-232, the Vortex EF-IR11 infrared controller, or from the units front panel; 16 factory presets and 32 user configurable presets allow quick selection of operating parameters Adaptable to user requirements Userprogrammable delays on all outputs, 5-band parametric EQ on all inputs and outputs, intelligent Automatic Gain Control, 256 macros, system diagnostics, and other tools ensure the best performance for all room conditions
Enjoy clear, understandable conversation in all conferencing applications.
The Vortex EF2280 improves audio quality for conferencing, distance learning, and other installed applications through industry-leading acoustic echo and noise cancellation - with support for up to 8 microphones. The Vortex EF2280 automatically mixes microphones and other audio sources while cancelling acoustic echoes and annoying background noise. It is typically installed at each site in a multi-site network and is commonly used in applications such as boardrooms, courtrooms, distance learning, sound reinforcement, and room combining. It connects easily to other equipment such as codecs, VCRs, or other A/V products. The unit can be programmed from the front panel, or through Conference Composer software (included). Conference Composer's InstantDesigner wizard ensures fast, accurate setup for a variety of applications. A single Vortex EF2280 unit provides automatic mixing of up to eight microphones plus four auxiliary audio sources. If more microphones are needed, additional Vortex EF2280 or Vortex EF2241 units can be linked, up to a total of eight units. Number of Open Microphones (NOM) information can be specified across all channels in the linked units. The microphone channels feature industry-leading acoustic echo cancellation to prevent retransmission of signals to their original locations. A neural network Automatic Gain Control (AGC) reacts only to valid speech patterns, bringing voices within desired levels. AGC controls are user adjustable, as are settings for the five-band parametric EQ offered on all input and output channels and output delay controls. The high-quality audio choice to access the power of Polycom unified collaborative communications solutions. With the greatest breadth and depth of integrated video, voice, and Web solutions, only Polycom delivers the ultimate communications experience. Our market-leading conferencing and collaboration technologies, supported by world-class service, enable people and organizations to maximize their effectiveness and productivity. Add to that the most experience and proven best-practices in the industry, and its clear why Polycom has become the smart choice for organizations seeking a strategic advantage in a real-time world.

Connect. Any Way You Want.
Polycom Vortex EF2280 Specifications
System Block Diagram and Rear Panel
Dimensions 19 (483 mm) W x 9.6 (244 mm) L x 1.75 (45 mm) H (one rack unit) Weight 4 lbs. (1.8 kg) dry, 5.5 lbs. (2.5 kg) shipping Connectors RS-232: DB9F EF Bus In/Out: RJ45 Control /Status: DB25F Audio: Mini (3.5mm) quick connect terminal blocks
Inputs Phantom power: 48 V DC, software selectable Analog input Gain: 0 to 30 dB Mic/line inputs in 1 dB steps, software adjustable Mic/Line switch gain: 33 dB Maximum input amplitude: +19 dBu, 1% THD + N Nominal level: 0 dBu (0.775V rms) Equivalent input noise: <-124 dBu, 20 - 20,000 Hz Input Impedance: 10 kOhms Input EMI Filter: Pi filter on all audio inputs Outputs Output Gain: -100 to 20 dBu in 1 dB steps, software adjustable Maximum output amplitude: +23 dBu, 1% THD + N Nominal output level: 0 dBu (0.775 V rms) Output impedance: 33 Ohm, each leg to ground Output EMI Filter: Pi filter on all audio outputs
Power External supply (provided) Input voltage of 110-240 VAC; 47-63 Hz; power consumption 30 W
System* Frequency response: 20-20,000 Hz, + 0.2 /- 0.3 dB Idle channel noise: <-100 dB FS "A" weighted, 20 - 20,000 Hz, 0 dB gain Dynamic range: >100 dB FS "A" weighted, 20 - 20,000 Hz, 0 dB gain Linearity: 0 dB FS to -110 dB FS +/- 1 dB THD+N: < -90 dB FS Common Mode Rejection Ratio: <-61 dB, 20 - 20,000 Hz, no weighting Cross talk: <-104 dB, 20-20,000 Hz, channel-to-channel Latency: Mic/Line inputs to outputs: 13 ms, processing enabled Acoustic Echo Cancellation Span: 270 ms Total Cancellation: >65 dB Convergence Rate: 40 dB/second Noise cancellation: 0-15 dB, software selectable Operating Temperature: 0 - 40 C Control Inputs: Contact closure Status Outputs: 5 V, 20 mA each *Unless noted, all values are valid for all channels at line level
2004 Polycom, Inc. All rights reserved.
Polycom, the Polycom logo and Vortex are registered trademarks and SoundStation VTX 1000, Conference Composer, InstantDesigner and VSX are trademarks of Polycom, Inc. in the U.S. and various countries. All other trademarks are the property of their respective companies. Specifications subject to change without notice. For Architect's and Engineer's Specifications, please visit Polycom.com, or contact the Installed Voice Business Group at 1.770.350.4140.

Polycom Headquarters:

www.polycom.com
4750 Willow Road, Pleasanton, CA 94588 (T) 1.800.POLYCOM (765.9266) for North America only. For North America, Latin America and Caribbean (T) +1.925.924.6000, (F) +1.925.924.Bath Road, Slough, Berkshire SL1 4DX, (T) +44 (0)1753 723000, (F) +44 (0)Polycom Hong Kong Ltd., Rm 1101 MassMutual Tower, 38 Gloucester Road, Wanchai, Hong Kong, (T) +852.2861.3113, (F)+852.2866.8028
Part No. 3726-82280-001 Rev. 10/04
Polycom EMEA: Polycom Asia Pacific:

Vortex EF2280 Reference Manual
VORTEX EF2280 REFERENCE MANUAL Introduction....2

Product Features.... 3

Pre-Installation....4
EF2280 Front and Rear Panels... 5

Installation....7

Mounting the EF2280... 7 Connecting the EF2280 to Other Equipment.. 7 Device IDs on the EF Bus.... 9 Connecting Multiple EF2280s... 9 Factory Default Settings (Preset 0).. 11 Check Surrounding Equipment... 13
Integrating the EF2280 Into Your System...15
Input Settings.... 15 Calibration.... 15 Build Your Echo Canceller Reference... 17 Echo Canceller Reference for Multiple EF2280s... 18 Configure the Automatic Microphone Mixer... 20 Automixer Settings for Multiple EF2280s.. 22 Configure the Matrix Mixer... 23 Building Your System with Multiple EF2280s... 23 Presets.... 25 Other EF2280 Features... 25

LCD Menu Structure...26

System Menu.... 29 Inputs..... 30 Outputs.... 31 Automixer Menu.... 32 Matrix Menu.... 34 Parametric EQ Menu.... 35

Troubleshooting...36

Automatic Microphone Mixer... 36 Matrix Mixer.... 37 Echo Canceller Reference... 37 Residual Echo.... 37 Contacting Technical Support... 42
Technical Specifications...43

Compliance.... 43

Conference System Design...46 EF2280 Block Diagram...47 Connector Pinouts...48
Connecting Unbalanced RCA to Balanced Mini Phoenix.. 50 Making an EF Bus Terminator... 50 Additional Notes.... 51
Warranty Information...52 Definition of Terms....54 Index....57
Polycom, Inc., Copyright 2001
Technical Support: 800.932.2774

INTRODUCTION

Welcome How to Use This Manual
Congratulations on your purchase of the Vortex EF2280!
This is a reference manual for your EF2280. It is structured to provide the information you need quickly and conveniently. The following is an overview of each section: Introduction Conference System Design gives suggestions on topics to consider when designing your system. Pre-Installation includes information about the contents of the box, tools needed for installation and front and rear panel descriptions. Installation covers connections of inputs/outputs and calibration of inputs of the EF2280. Integrating the EF2280 Into Your System describes adjustments to take into consideration when integrating the EF2280 with surrounding equipment in your system. LCD Menu Structure describes an overview of the LCD menu structure and also gives a system overview of features and options available. Troubleshooting helps to debug problems with installation. Technical Specifications provides the technical specifications of the EF2280. EF2280 Block Diagram shows the inside of the EF2280. Connector Pinouts shows pinout diagrams for EF2280 input and output connectors. Warranty Information Definition of Terms explains terms used in this manual, as well as terms used in our technology of echo cancellation, noise cancellation, and audio conferencing.

About the EF2280

The EF2280 is a 12-input, 12-output, 8-channel acoustic echo and noise canceller with matrix mixing and automatic microphone mixing capabilities. It includes a total of 12 analog inputs (8 mic/line level inputs and 4 line level inputs), 12 analog outputs, and 4 digital expansion busses. Acoustic echo cancellation (AEC) and noise cancellation can be applied to each of the 8 mic/line level inputs, and each of these inputs can then be sent to one of the two internal automatic microphone mixers. The system also contains a 25 x 18 main matrix, and four 7 x 3 submatrices. The 25 x 18 main matrix has the following inputs: input channels 1-8 (gated or ungated), input channels A-D, the internal signal generator, and 3 mixes of each of the four digital busses (3 mixes times 4 busses equals 12 inputs). The 25 x 18 main matrix has the following outputs: outputs 1-8 and A-D, AEC reference 1 and 2, and W, X, Y, and Z outputs to the digital expansion bus. The EF2280 has 24 bit resolution, 32-bit floating point computation, and a 48 kHz sampling rate. Polycoms proprietary noise cancellation on each of the 8 mic/line inputs helps to keep overall ambient noise to a minimum. Polycom echo cancellers are the only ones on the market to feature this patent pending technology. Noise cancellation filters out ambient background noise such as noise from heating, ventilating and air conditioning (HVAC), LCD projectors, and road noise. Our noise cancellation technology is not a noise gate. It actually removes noise. Therefore, it enhances the operation and

Fine tune the Input Gain using the Automatic Gain Control (AGC) meter on Conference Composer Software. In the Conference Composer
Software, go to the DIAGNOSTICS page. Watch the meter labelled AGC while someone is talking into the particular channel that you are adjusting. Watch the number in the box at the bottom of the AGC meter (See Figure 10 below). This is the amount of gain that the AGC is applying. The goal is to have the AGC meter on average staying around 0. If the level that you see in the box is negative, decrease the input gain by the average number that you see in the box because the AGC is attenuating the channels input gain because the level is too high. If the number in the box is positive, increase the input gain on that channel because the AGC is boosting the signal because it is too low. For example, if the meter is showing an average gain of -15 dB,
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 le

Adjust Input Gain here

Figure 10. AGC Meter on the Diagnostics page of the Conference Composer software.
IF THE AGC METER SHOWS. positive gain negative gain an average level of 0 dB
ADJUST THE INPUT GAIN IN THIS WAY. Increase gain by the level shown in the box. Decrease gain by the level shown in the box. Youve set the Input Gain to a good level!
Table 1: How to set the Input Gain using the AGC meter on the Conference Composer Diagnostics page.
Set Levels on Line Input Channels
Set the line input channel gains (Channels A-D) to match the nominal level of the incoming equipment. The line inputs have a maximum nominal level of 0 dBu. If your incoming line level inputs have a higher nominal level than 0 dBu you will want to use a pad to remove the level.
INTEGRATING THE EF2280 INTO YOUR SYSTEM Customize Setting for Your Particular Application
The following sections will describe customizing parameters on the EF2280 for your particular application if you are not using Preset 0.
BUILD YOUR ECHO CANCELLER REFERENCE
The acoustic echo canceller (AEC) reference should generally contain exactly the same audio signals as what is coming out of your loudspeaker(s), since the signal output from the loudspeaker is what is then picked up by the rooms microphones causing acoustic echo. Note that this statement is a general statement. Conditions for this being true follow:
If your system does NOT have sound reinforcement,
The AEC reference should contain exactly the same audio as the loudspeaker output: all far end audio, audio from the phone add, program audio, etc. If your system contains stereo inputs and outputs, the reference must contain a mix of both stereo inputs. For example, if your VCR audio is in stereo, the reference should contain both the left and right signals each attenuated by 3 dB, as well as any other audio that is going to your loudspeaker. If you are using crosspoint gains in the loudspeaker mix, apply the same gains to the signals in your reference.

If your system has sound reinforcement,
Do NOT mix your room microphones into the reference, but include all other audio (program audio, remote audio, phone audio, etc.). An exception to this rule is when you use one EF2280 split to operate independently in two rooms. If the two rooms communicate with each other (along with communicating via codec and the phone line), the reference in the first room must contain the microphones from the second room and vice versa. See Figure 11 below.
If Room 1's loudspeaker contains a mix of Room 2's microphones, then Room 1's AEC reference should also contain Room 2's microphones. The same is true for Room 2's AEC reference.

From AEC

To AEC To Rem.

Polycom Video CODEC

Line In Line Out

From Rem.

Phone PSTN
Figure 11. AEC reference for two rooms that communicate with each other with one EF2280.
ECHO CANCELLER REFERENCE FOR MULTIPLE EF2280S
In a system with multiple devices, we recommend that one device be designated as the unit that provides the EF bus reference for the acoustic echo cancellers. This unit takes one of its reference signals (either Ref 1 or Ref 2) and places it on the EF bus. All other units that are linked together may use the EF bus reference as the reference 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 29).
Setting up the Bus Reference
If all far end audio and program audio sources are on the same EF2280,
1. 2. Assign far end audio and program audio sources to Reference 1 on the originating EF2280. On the EF Bus page in Conference Composer for the originating EF2280, set the Exported Signals to REFERENCE 1. Only one EF2280 can put an echo canceller reference on the EF Bus as the Bus Reference. On all linked EF2280s, set the echo canceller reference to BUS.
For example, a system uses 2 EF2280s, 1 EF200, and 1 Polycom VS4000 video codec. The originating sources for far end audio is EF2280 with ID 0. The Matrix for
this EF2280 in Conference Composer is shown in Figure 12 and the EF Bus page in Figure 13. Conference Composer will not allow more than one EF2280 assign their echo canceller reference as the Bus Reference. Notice that the EF200 and VS4000 inputs are both assigned to Reference 1 on the originating EF2280. The Matrix for any linked EF2280s is shown in Figure 14.
Figure 12. Matrix page of origin EF2280 (ID 00)
Figure 13. EF Bus page of origin EF2280 (ID 00)
Figure 14. Matrix page of linked EF2280s
INTEGRATING THE EF2280 INTO YOUR SYSTEM If far end audio and program audio sources are on several EF2280s,
1. 2. Bus each far end audio and program audio source to each EF2280. Do this by assigning each signal input to either the W, X, Y or Z bus. Assign an echo canceller reference on each EF2280 that will include all far end audio and program audio sources.

CONFIGURE THE AUTOMATIC MICROPHONE MIXER
The EF2280 contains two independent automatic microphone mixers. Each input may be assigned to automatic mixer 1, automatic mixer 2, or neither (but not both). Assign all microphones to the same automixer when using all microphones in the same room but in different zones, so that a person does not activate microphones in two different zones (which they would tend to do if each zone had its own automatic mixer). Use both automatic mixers when the EF2280 is split to operate independently between two rooms. One automatic mixer is used in each room. The advantage of having two independent automatic mixers is that when used in two rooms, microphone signals in one room do not affect the gating behavior of microphones in the other room. Set an input channel to use neither automatic mixer if an input is not actually a microphone, but is a program audio input. For instance, if you only have 6 microphones and you have an extra stereo program audio source that you want automatic gain control (AGC) on and/or noise cancel, you could set its channels to be on neither automatic mixer. If you have a PC, use the Conference Composer software (See the Conference Composer User Guide) to set the automixer parameters. If you would like to set automixer parameters using the LCD menus, see Automixer Menu on page 32 for instructions on setting automixer parameters.

Automixer Parameters

The following parameters configure how the EF2280 automatic microphone mixer operates. Parameters include the following: Decay Time, Hold Time, Camera Gating Threshold, Chairman Mode, Chairman Mic, Last Mic On Mode, Last Mic Number, Local Max NOM, Global Max NOM, Off Attenuation, Threshold Type, Gating Mode, Gate Ratio, Manual Threshold, and Microphone Priority.

Signal Level

Channel turns on when signal level is above gate ratio DECAY TIME Channel ON GATE R ATIO Channel OFF Ambient Level Microphone Audio HOLD TIME OFF A TTENUATION
Figure 15. Off Attenuation, Hold Time, Gate Ratio, and Decay Time.
INTEGRATING THE EF2280 INTO YOUR SYSTEM Global Settings.
Decay Time. Decay time is the amount of time the microphone audio takes to ramp down to the Off Attenuation level after Hold Time. Decay Time values range from 0 to 5000 msec. The default value is 1000 msec. Hold Time. This is the amount of time the microphone stays On after the energy in the channel drops below the gating threshold. The default value is 500 msec. The range is 1 to 5000 msec. Microphone channels gating On and Off too frequently during short pauses in speech might be the result of setting the Hold Time too low while too many microphones gating on at the same time may be the result of Hold Time values that are too high. Camera Gating Threshold. Specifies the hold time for camera gating information.

Mixer Settings.

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 EF2280s each of which has four microphones assigned to Automixer 1 and 4 microphones assigned to Automixer 2. Now, if each of these EF2280s sets their Automixer 1 to use Bus Mixer 5, then the three automixers (one from each EF2280) will work as a single automixer containing 12 (3 x 4) microphones. Setting Bus Mixer to 0 means that the automixer is not grouped on the EF Bus. Chairman Mode. Enables or disables Chairman Mode for the specified automixer. Chairman Mic. Sets the Chairman Microphone for the specified automixer. Last Mic On Mode. Sets Last Mic On mode for the specified automixer. Last Mic Number. Sets the microphone number that will remain on when Last Mic On mode is set to manual. Setting this value to 0 will cause the automixer to leave the last open microphone on. The last microphone number is specified for each automixer, but is only used in manual Last Mic On mode. Local Max NOM. Sets the maximum number of open microphones (NOM) limit for the specified automixer. This NOM limit is a local limit, meaning that this limit applies only to the specific EF2280 that it is set on. Global Max NOM. Sets the global maximum number of open microphones (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.

INTEGRATING THE EF2280 INTO YOUR SYSTEM Operating as an Independent Automixer Operating as One Automixer with Multiple EF2280s Default Settings
To set the EF2280 to operate as an independent automixer (or two), set the BUS MIXER parameter to 0, or to a number that is different from any other automixer group on the EF Bus.
To set the EF2280 to operate as one automixer across several EF2280s, set the BUS MIXER parameter on all EF2280s to the same automixer group.
In the default preset (Preset 0), the Bus Mixer for Automixer 1 is set to 1 and the Bus Mixer for Automixer 2 is set to 2. This means that in the default mode, all linked EF2280s will work together as one complete automixer.
CONFIGURE THE MATRIX MIXER
The matrix mixer allows arbitrary crosspoint gains in 1 dB increments between any input and output signal. If you have a PC, use the Conference Composer software (See the Conference Composer User Guide) to set the matrix parameters. If you would like to set matrix parameters from the LCD menus, see Matrix Menu on page 34 for descriptions and instructions on setting matrix mixer parameters.
BUILDING YOUR SYSTEM WITH MULTIPLE EF2280S
The following is a checklist for building a system with mutliple EF2280s: 1. 2. 3. 4. Assign Inputs. Assign Outputs. Configure submatrix (the EF Bus). Configure your echo canceller reference.

1. Assign Inputs

Assign each audio source to an input. Remember to include the conferencing equipment such as the EF200 Phone Add or a video codec and any program audio.

2. Assign Outputs

Try to assign as many outputs as you can to each EF2280 to make a simpler submatrix. Remember that Outputs 1-8 can also be used as outputs of the matrix. The bussing can get very complicated very quickly if you choose to spread your outputs over several units.
3. Configure the submatrix.
To link multiple EF2280 devices together, use the submatrix on the EF Bus.
INTEGRATING THE EF2280 INTO YOUR SYSTEM The EF Bus
The EF Bus is a high speed, low delay digital bus that includes the W, X, Y, and Z audio busses as well as the echo canceller reference and remote control information (for other EF2280s) and can link up to 8 EF2280 devices. All busses include NOM information and can be used for sharing microphone inputs, or for sharing mono or stereo program information.
Crosspoint Mix Minus Bus. Each EF2280 device in the system can create
four output mixes (W, X, Y, and Z) and place them on the bus. Each device also can create three input mixes each from the W, X, Y, and Z busses of the other devices (for a total of 12 mixes). The mixes can have crosspoint gains on the signals from the other devices. See Figure 17 below. All 12 mixes become inputs to the main matrix and can be mixed with the other inputs to create outputs 1-8, A-D, Ref 1, Ref 2, and W, X, Y, and Z bus outputs.

Device ID. Selects the Device ID of the unit. LCD Contrast. Controls the contrast level of the front panel liquid crystal display
(LCD). Higher numbers result in darker characters on the display, lower numbers result in lighter characters.
Meter. Selects which signal is displayed on the front panel LED meter. Non-Volatile Memory Lock. Controls the non-volatile lock feature. When
the non-volatile memory is locked, you can query the settings but will get an error if you try to change them.
Non-Volatile Memory Password. This feature sets or queries the non-volaORY
tile lock password. This password is used in conjunction with NON-VOLATILE MEMLOCK. The default password is aspi (case is important).
Screen Saver. Enables or disables the screen saver on the LCD panel. You can

also set the idle time.

Figure 19. EF2280 System submenu
Software Version. Queries the software version. Reboot EF2280. Cycles power on the EF2280.

INPUTS

The input menu allows the user to adjust functions related to the input signals to the EF2280. This menu contains ACOUSTIC ECHO CANCELLATION, AUTOMATIC GAIN CONTROL, AGC MAXIMUM, AGC MINIMUM, GAIN ADJUST, LEVEL MIC/LINE, MUTE, NOISE CANCELLATION, NOISE CANCELLATION LEVEL, PHANTOM POWER, REFERENCE ASSIGN, and AEC SUPPRESSION. The menu is organized around the Inputs (1-8) and (A-D), so that you first select an input and then select settings for that input. You can also choose to apply the settings to all Inputs, Inputs 1-8, or Inputs AD.
Acoustic Echo Cancellation. This allows you to enable or disable the acoustic
echo canceller on a particular channel. The default is On.
Automatic Gain Control. This enables automatic gain control (AGC) on
Inputs 1-8. The default is On.
AGC Max. Sets the maximum gain value that the AGC can apply. AGC Min. Sets the minimum gain value that the AGC can apply. Gain. This parameter adjusts the gain level of the 12 inputs. This is normally configured during the calibration process. The default setting is 15 dB for microphone signals and 0 dBu for line level signals. See Level above for setting mic/line level for Inputs 1-8. The LEVEL INDICATOR on the front panel automatically reflects the level of the channel whose gain is being adjusted. Figure 21 below shows the gain adjust on Inputs 1-8 and A-D and the matrix crosspoints.

Input Channel (1 of 8)

Matrix Cross point

Output Channel (1 of 12)

Mic Preamp Adjustable 33 to 53 dB

MATRIX MIXER

Dont hear output
Make sure the output is not muted. Check that the input youre expecting to hear is included in the output that youre listening to.

ECHO CANCELLER REFERENCE

Room Audio Sounds Choppy
If you hear the local rooms audio from the loudspeakers and it sounds choppy, you may have included the rooms microphones in the echo canceller reference. The echo canceller reference should NOT include the local rooms microphones -- it should only contain the remote ends audio and program audio. You can still add the local rooms microphones to the local output with the matrix, but do not add them to the echo canceller reference. For more specific guidelines on what to include in your echo canceller reference, see Build Your Echo Canceller Reference on page 17.

RESIDUAL ECHO

You may hear residual echo if system levels are not set properly. Improper level settings anywhere in the audio path can introduce nonlinearities that hamper the operation of the EF2280. If you hear residual echo, one of the following conditions may be causing the problem.
Reverberation vs. Acoustic Echo
Do not confuse the residual echo of remote speech with the reverberation of local speech. Reverberation of local speech is caused when the speech signal arrives at the microphone via several paths (the direct path and multiple reflections from surfaces in the room). This is a local room phenomenon that gives the talkers voice a hollow or resonant sound (as heard at the remote end).
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. If the remote end complains that they hear echo, ensure that they are referring to hearing their own voice and not echoes of local talkers. You cannot remove the effects of reverberation by changing the EF2280s settings, but you can minimize reverberation by moving microphones closer to talkers and, if necessary, adding acoustical treatment to the room.
Finding the Source of Echo

VCCI Class A

Rest of World EMC CLASS A ITE
WARNING This is a Class A product. In a domestic environment this product may cause radio interference in which case the user may be required to take adequate measures.
TECHNICAL SPECIFICATIONS Installation Instructions*
Installation must be performed in accordance with all relevant national wiring rules. LInstallation doit tre excute conformment tous les rglements nationaux applicable au filage lectrique.
Plug acts as Disconnect Device*
The socket outlet to which this apparatus is connected must be installed near the equipment and must always be readily accessible

CONFERENCE SYSTEM DESIGN

Good audio or video conferencing is more than acoustic echo cancellation. Before installing the EF2280, you should consider how your whole conference system will work together. The goals of conference system design are the following: Transmit intelligible speech Reproduce received speech intelligibly Prevent echoes Interface properly with transmission equipment High quality program audio Intelligible sound reinforcement (if needed)

Noise and Reverberation

Intelligibility can be affected by noise and reverberation. Noise comes from various sources such as HVAC, computers, projectors, or traffic. Some ways to improve the Signal to Noise Ratio (SNR) in your system include placing microphones closer to the talkers, using electronic noise cancellation, and applying acoustical treatments. The EF2280 is a great way to reduce noise in your system and improve the SNR. Polycoms patent pending noise cancellation algorithm, included in the EF2280, removes up to 10 dB of ambient background noise and improves perceived quality as well as intelligibility. Reverberation in a conference system can reduce intelligibility in a room. To reduce reverberation and increase intelligibility, use directional microphone and loudspeakers, place microphones closer to the talker, and use acoustical treatment.

Consider Room Gain

When planning your conferencing system, you should also consider the room gain that will occur as a result of your microphone and loudspeaker placement. Room gain refers to the relative level of the audio going to your amplifier (remote end speech or telephone speech) and the level of this audio being picked up by the microphone. We recommend a room gain of 0 dB or less for the best results. But for difficult acoustic environments, the EF2280, as well as any of the EF products, can handle up to 10 dB room gain, which means that it offers great flexibility in your conference system design. To help you measure room gain, the EF2280 includes a room gain detector. You should check your room gain after you have set up the EF2280.

Figure 29. Room Gain.

Output 1

Output 2

Output 3

Output 4

Output 5

Output 6

Output 7

Output 8

Output A

Output B

Output C

Output D

EF2280 BLOCK DIAGRAM
Figure 30. Inside the EF2280
Delay Delay Delay Delay Delay Delay Delay Delay Delay Delay Delay Delay PEQ PEQ PEQ PEQ PEQ PEQ PEQ PEQ PEQ PEQ PEQ PEQ RS-232 Matrixing ASPI Bus Control/Status EN EN EN EN EN EN EN EN PEQ PEQ PEQ PEQ EF Bus
A/D A/D A/D A/D A/D A/D A/D A/D A/D
Level adjust Level adjust Level adjust Level adjust Level adjust Level adjust Level adjust Level adjust Level adjust
Phantom Mic/Line Phantom Phantom Phantom Phantom Phantom Phantom Phantom

Level adjust

Mic/Line
Mic/Line 1 Mic/Line 2 Mic/Line 3 Mic/Line 4 Mic/Line 5 Mic/Line 6 Mic/Line 7 Mic/Line 8

Input A

Input B

Input C

Input D
EN (Echo Canceller, Noise Canceller)
Ungated Echo Canceller EC1, EC2, Bus On Off Noise Canceller AGC On Off PEQ Parameters Mute On Off Gate Parameters Gated

CONNECTOR PINOUTS

EF Bus

EF BUS IN

EF BUS OUT
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 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. Cat-5 Plug Pinout

Cat 5 Plug (Front View)

1 - White/Orange 2 - Orange 3 - White/Green 4 - Blue 5 - White/Blue 6 - Green 7 - White/Brown 8 - Brown
ASPI Bus The ASPI Bus uses RJ45 connectors. These should be used with category five twisted-pair cable. The total distance of the ASPI Bus should be less than 15 m. RS-232 Port (9600 8-N-1)

ASPI BUS

RS-232
The RS-232 port is wired as DCE. It accepts a male DB-9 connector. Only pins 2, 3, and 5 are required by the EF2280 but pins 7 and 8 are supported. Connect pins straight through (do not use null modem). 1 DCD; 2 TXD; 3 RXD 4 DSR; 5 ground; 6 DTR; 7 CTS; 8 RTS; 9 No connection
Input/Output Remote Control Port

INPUT REMOTE CONTROL

Logic Input: Pins 1-24 are inputs 1-24, respectively. Pin 25 is ground. 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. LEDs can be used without series resistors (we have provided series resistors in the circuitry). For best results, LEDs with Vf=2.0 V and If=20 mA should be used. Larger values may be used, but may result in dimmer LEDs. An LED with Vf less than 1.4 V should not be used without additional series resistance. Power Supply Input

OUTPUT

5, 15 VDC 12 15
The power supply input accepts a 5-pin DIN male connector. Only use the power supply provided by Polycom. Use of other power supplies will void the warranty. 1 Ground; 2 Ground; 3 +5Vdc @ 3 A; 4 -15Vdc @ 0.3 A; 5 +15Vdc @ 1.2 A
Mic/Line Inputs, Line Inputs, Line Outputs These audio connectors accept a mini (3.5 mm) 3 conductor terminal block (provided). See Note below for manufacturer information. From left to right the conductors are positive signal, negative signal, and shield ground.
The information below lists manufacturer information for the Phoenix connector that is compatible with the parts we use: Manufacturer: Phoenix Contact Description: Mini-COMBICON 3-position plug, 3.5 mm pitch Type Number: MC 1.5/3-ST-3.5 or MC 1,5/3-ST-3,5 Part Number: 1840379 For proper operation, a ferrite should be positioned on control and data cables.
CONNECTING UNBALANCED RCA TO BALANCED MINI PHOENIX

RCA Male

Tip Red Black Ring

Mini (3.5 mm) Phoenix

Red + Black Shield 3
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. Caution! On the EF2280, Phoenix pin 3 is connected to
chassis ground. Under no circumstances should Phoenix pin 3 be connected to pin 1 or to pin 2. Doing so will add noise to the audio signal.
MAKING AN EF BUS TERMINATOR

12345678

Figure 32. The EF2280 terminator

Instructions

To make a EF2280 terminator, use an RJ45 connector. Connect pin 3 to pin 6 with an 110 Ohm resistor.

ADDITIONAL NOTES

Caution! Caution! Caution! Failure to use all four screws to attach the EF2280 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 EF2280 in a rack, consideration should be given to airflow and operating ambient temperatures inside the rack. To ensure safe operation of the EF2280, ambient operating temperatures inside the rack should not exceed 40 degrees Celsius. Allow 2 inches (51mm) of open space in front of the EF2280, 2 inches (51mm) on either side, and 4 inches (102 mm) behind the unit for proper ventilation. Equipment should not be installed in the rack in such a way as to interfere with the ventilation of the EF2280. Consideration should be given to the connection of the equipment to the supply circuit and the effect that overloading of circuits could have an 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).

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. If your Polycom EF2280 product is not covered by our warranty, call us at (800) 9322774 or fax us at (404) 892-2512 for advice about whether we will repair your Polycom EF2280 product and for other repair information, including charges. Polycom, at its sole discretion, may replace rather than repair your Polycom EF2280 product with a new or reconditioned one of the same or similar design. The repair or replacement is warranted for 90 days. The limited warranties and remedies set forth above are exclusive and in lieu of all other warranties, whether oral or written, express or implied. Polycom specifically disclaims any and all implied warranties, including, without limitation, the warranties of merchantability and fitness for a particular purpose.
No User Serviceable Parts
This product contains no user serviceable parts. Please contact Polycom Installed Voice Business Group for repairs. Attempts to repair this product by an unauthorized technician will void your warranty.

State Law Rights

This limited warranty gives you specific legal rights, and you any have other rights that may vary from state to state.

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. It refers to how much louder the audio is with sound reinforcement compared to without sound reinforcement.

Ambient Level

The ambient level, also referred to as noise floor, is the background noise heard in a room when no one on the near or remote end is talking.

The ASPI Bus

The ASPI bus is used to link EF devices for RS-232 control using a single controller, such as a touch panel or PC.
Automatic Gain Control (AGC) Automatic Microphone Mixer Convergence Rate
Automatic gain control increases or decreases the gain on an audio signal to an acceptable value.
A microphone mixer that turns microphone channels on and off based on the signal level going into the microphone.

Convergence rate refers to the amount of echo a line or acoustic echo canceller can cancel per unit time, typically expressed in dB/sec. Better echo cancellers have a higher (faster) convergence rate. This term is typically used to quantify the time it takes to completely remove the echo from a conferencing system. Echo occurs due to a complete change of the acoustic environment such as the beginning of a phone call in a conference, a change of microphone-speaker placement, or speaker volume adjustment.

Crosspoint Mix Minus Bus

A mix minus bus allows each device (i.e., a EF2280 unit) to create a mix of signals without its own. Each device in the system can create four mixes (W, X, Y, and Z) and place them on the bus. Each device also can create three mixes each from the W, X, Y, and Z busses of the other devices (for a total of 12 mixes). One mix is hardwired as a normal mix minus. That is, it is a unity gain mix of the signals from all other devices. The other two mixes can have crosspoint gains on the signals from the other devices.
DEFINITION OF TERMS Echo Canceller
An echo canceller estimates the echo in an audio signal by using a reference and preforms processing to eliminate the echo from the signal.
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 EF2280 devices.

Equalization Line Echo

Equalization is the process of adjusting frequency characteristics of an audio signal.
Line echo is caused by reflections of the audio signal from the telephone hybrid. The EF200 Phone Add is an example of a unit that has a line echo canceller.

Macros Matrix Mixer

An arbitrary set of commands that can be replayed.
A matrix mixer allows you to choose which inputs are included in each output. Some matrix mixers allow you to assign crosspoint gains to the inputs.

Noise Cancellation

Noise cancellation is a digital signal process that removes noise from an audio signal corrupted by real-world interferences such as HVAC, office noise, crowd noise, or road noise. Generally, there are two parts of a noise cancellation algorithm: a method to detect the noise and a method to remove the noise. The Polycom noise cancellation algorithm (patent pending) is capable of removing 10 dB or higher of noise with no degradation at all to the resulting speech signal. This method does not attenuate speech, and removes noise during both speech and idle periods.

NOM NOM Attenuation

NOM refers to the number of open microphones in a system.