DATAPixx3 Video I/O Hub

If you are looking for the user manual for the DATAPixx2, see this page.

Product Overview

The DATAPixx3 is an advanced multi-function data and video processing USB peripheral designed for vision research. It acts as a controller for the TRACKPixx3 eye tracker and the PROPixx projector. It integrates a dual-display video processor with peripherals for precise synchronization with video during experiments. These peripherals include:

• Button box interface

• 24 TTL trigger inputs and outputs

• Stereo audio input and output

• Analog inputs and outputs

• Interface for 3D glasses

• VideoBahn interface for TRACKPixx3 eye tracker

By implementing video control and peripheral management on the same circuit board, the DATAPixx3 ensures microsecond precision in synchronizing all subject I/O with visual stimuli.

To learn more, check out our DATAPixx3 Product Tour on YouTube!

Product Details

This section includes detailed information about the various ports of the DATAPixx3 Video I/O hub. Expand the relevant section to view details about the device subsystem, including technical specifications and pin assignment.

1. Digital output

Digital output

The DATAPixx3 supports TTL digital outputs via a DB25 port on the rear of the unit (highlighted below).
TTL stands for transistor-transistor logic, which is a simple digital communication protocol that consists of rising and falling voltages. It is commonly used for rapid, simple communication between electronic devices. Common applications in research include sending TTL “triggers” to signal events like visual stimulus onset to third-party systems.

Technical specifications:

• 24 digital outputs on DB25 connector (female)

• Output drive stage: 5 V through 25 Ω series resistor

• Maximum output current:

  • Source: 15 mA

  • Sink: 12 mA

Detailed pin assignment information:

Below are the industry standard pin labels and their corresponding function. Pins 1-12 are configured for even digital output channels from 0-22; pins 12-25 are configured for odd digital output channels from 1-23; pin 13 is ground. Note that pin numbering follows the industry standard for DB25 ports.

Pin	Description	Pin	Description
1	Digital Out 0	14	Digital Out 1
2	Digital Out 2	15	Digital Out 3
3	Digital Out 4	16	Digital Out 5
4	Digital Out 6	17	Digital Out 7
5	Digital Out 8	18	Digital Out 9
6	Digital Out 10	19	Digital Out 11
7	Digital Out 12	20	Digital Out 13
8	Digital Out 14	21	Digital Out 15
9	Digital Out 16	22	Digital Out 17
10	Digital Out 18	23	Digital Out 19
11	Digital Out 20	24	Digital Out 21
12	Digital Out 22	25	Digital Out 23
13	GND	Shield *

*Shield is tied to the GND by a 0 Ohm resistor inside the DATAPixx3.

2. Digital input

Digital input

The DATAPixx3 supports TTL digital inputs via a DB25 port on the rear of the unit (highlighted below).
TTL stands for transistor-transistor logic, which is a simple digital communication protocol that consists of rising and falling voltages. It is commonly used for rapid, simple communication between electronic devices. Common applications in research include receiving high-speed input from TTL-based button boxes and MRI triggers.

Technical specifications:

• 24 inputs on DB25 connector (female)

• Input termination: >20 kΩ pull-up to 3.3 V

• Input tolerance: 5 V

Detailed pin assignment information:

Below are the industry standard pin labels and their corresponding function. Pins 1-12 are configured for even digital input channels from 0-22; pins 12-25 are configured for odd digital input channels from 1-23; pin 13 is ground. Note that pin numbering follows the industry standard for DB25 ports.

Pin	Description	Pin	Description
1	Digital In 0	14	Digital In 1
2	Digital In 2	15	Digital In 3
3	Digital In 4	16	Digital In 5
4	Digital In 6	17	Digital In 7
5	Digital In 8	18	Digital In 9
6	Digital In 10	19	Digital In 11
7	Digital In 12	20	Digital In 13
8	Digital In 14	21	Digital In 15
9	Digital In 16	22	Digital In 17
10	Digital In 18	23	Digital In 19
11	Digital In 20	24	Digital In 21
12	Digital In 22	25	Digital In 23
13	GND	Shield *

*Shield is tied to the GND by a 0 Ohm resistor inside the DATAPixx3.

3. Combined analog input/output

“Full” vs. “Lite” Systems: As of September 2023, all VPixx data acquisition systems include analog and audio I/O functionality. Units sold before this were either Lite or Full models; only Full models have analog and audio I/O features enabled. Depending on the age and model of your device, you may not have access to these features. For more details, see our FAQ.

Combined analog input/output

Analog signals are continuous voltages that vary over time and are used to record fluctuating variables like position, force and energy. They are also the foundation for audio output. Modern systems digitize analog signals using Analog to Digital Converters (ADC) and convert digital signals back into analog using Digital to Analog Converters (DAC). The DATAPixx3 features 16 ADC channels (or 8 differential channels) and 4 DAC channels on a single DB25 port on the rear of the unit.

Technical specifications:

Analog to digital converter

• Number of channels: 16 (or 8 differential), on DB-25

• Converter resolution: 16 bits

• Maximum sampling rate: 200 kSPS per channel

• Frequency programming modes:

  • samples per second or per video frame

  • nanoseconds per sample

• Simultaneous sampling across all channels

• Input range: ±10 V

• Input impedance: 1.6*10⁸ Ω // 3 pF

• Absolute maximum input tolerance: ±12 V

Digital to analog converter

• Number of channels: 4 on DB-25 connector

• Converter resolution: 16 bits

• Maximum sampling rate: 1 MSPS per channel

• Frequency programming modes:

  • samples per second or per video frame

  • nanoseconds per sample

• Simultaneous output updates

• Output range: ±10 V on 4 ch

• Drive capability: ±25 mA

Detailed pin assignment information:

Below are the industry-standard pin labels and their corresponding functions. Note that pin numbering follows the industry standard for DB25 ports.

Pin	Description	Pin	Description
1	ADC0	14	ADC1
2	ADC2	15	ADC3
3	ADC4	16	ADC5
4	ADC6	17	ADC7
5	ADC8	18	ADC9
6	ADC10	19	ADC11
7	ADC12	20	ADC13
8	ADC14	21	ADC15
9	REF0	22	REF1
10	GND	23	+5 VDC **
11	DAC0	24	DAC1
12	DAC2	25	DAC3
13	GND	Shield *

*Shield is tied to the GND by a 0 Ohm resistor inside the DATAPixx3.
** Current limited (400mA).

4. Audio input/output

“Full” vs. “Lite” Systems: As of September 2023, all VPixx data acquisition systems include analog and audio I/O functionality. Units sold before this were either Lite or Full models; only Full models have analog and audio I/O features enabled. Depending on the age and model of your device, you may not have access to these features. For more details, see our FAQ.

Audio input/output

The DATAPixx3 supports audio output, audio input and microphone input on 3 3.5 mm stereo jacks on the device's rear.

The audio out port plays audio waveforms uploaded to DATAPixx3 device memory with microsecond-precise timing and supports various sound systems, from speakers to headphones.

Audio in and mic in are both used to record audio from other sources and save the input to the DATAPixx3 memory for later transfer to your experiment PC.

Technical specifications:

• Audio line in, microphone in, speaker out, on 3.5 mm jacks

• Stereo microphone input amplifier resistance: 20 kΩ

• Microphone sampling rate: 96 kHz

• Programmable microphone bias voltage range: 2.0 V to 3.1 V

• Stereo DAC sampling rate: 96 kHz

• Maximum output power into 8 Ω load: 500 mW

Detailed pin assignment information:

Audio In
Pin	Description
Tip	Audio In left
Ring	Audio In Right
Sleeve	GND
Shield *

*Shield is tied to the GND by a 0 Ohm resistor inside the DATAPixx3.

Audio Out
Pin	Description
TIP	Audio Out left
Ring	Audio Out Right
Sleeve	GND
Shield *

*Shield is tied to the GND by a 0 Ohm resistor inside the DATAPixx3.

Microphone In
Pin	Description
TIP	Microphone In left
Ring	Microphone In Right
Sleeve	GND
Shield *

*Shield is tied to the GND by a 0 Ohm resistor inside the DATAPixx3.

5. VESA 3D interface

VESA 3D interface

The DATAPixx3's VESA 3D interface enables 3D stimulus presentation with a screen connected to the DisplayPort interface. A VESA-compliant system like the 3DPixx must be connected to use 3D features.

Detailed pin assignment information:

Below are the industry standard pin labels and their corresponding function.

Pin	Description
1	+5 VDC **
2	GND
3	VESA_LR (+5 VDC)
Shield*

*Shield is tied to the GND by a 0 Ohm resistor inside the DATAPixx3.
**Current limited (400mA).

6. DisplayPort interface

DisplayPort interface

The DATAPixx3 sits in the video chain between your experiment PC and your display. It receives a copy of the video output from your PC via the IN 1 port on the rear of the unit and passes it to your stimulus display via the OUT 1 port. The DATAPixx3 can be configured to monitor the properties of the video signal for timing and synchronization purposes.

An optional second display can be connected to OUT 2. This display will mirror the contents of OUT 1 without adding any load to your graphics processor. We call this secondary display the “console” display. The researcher typically uses it to the progress of the experiment from their control station. Unique information, such as an eye-tracking live feed or “hidden” metadata, can be shown on the console depending on the device connected and the video mode used.

Currently, the IN 2 port is reserved for future product development and is not in use.

Technical specifications:

• 2x DisplayPort 1.4 inputs (32.8 Gb/sec on each input)

• 2x DisplayPort 1.4 outputs (32.8 Gb/sec on each output)

• Video output format: One stimulus display and one console display

7. Videobahn fibre optic interface

Videobahn fibre optic interface

The DATAPixx3 supports fibre optic communication over a proprietary high-speed Videobahn protocol. Four slots on the back of the unit allow this. These connections are used, for example, for rapid data transmission and control of the TRACKPixx3 2 kHz eye tracker.

Technical specifications:

• 4 Videobahn interfaces are available. Each one can carry up to 48 Gb/sec of video and data in each direction.

8. USB-B interface

USB-B interface

The DATAPixx3 connects to your experiment PC via a USB connection. The connection port is shown below:

Technical specifications:

• USB 2.0 with 480 Mbit/s theoretical maximum bandwidth

9. 12V power output

12V power output

The DATAPixx3 can provide 12V DC power to specific external devices during operation. Examples include:

• TRACKPixx3 eye tracking camera and illuminator (rightmost port only)

• RESPONSEPixx /MRI control unit

• Certain models of DisplayPort to Dual-Link DVI adapter

There are three 12V DC 2-pin female LEMO sockets and one 8-pin female socket available. To connect a device to the power supply, ensure the corresponding LEMO connector has the appropriate number of pins and power requirements for the port.

Connectors have a small orange dot indicating which side of the connector should point upwards. The textured metal ring around the connector slides back for cable insertion. Ensure the connector is firmly attached to the port during operation.

Technical specifications

• 4 power output connectors, each one able to supply a stable +12V DC

• 3x 2-pin connectors, 1x 8-pin connector

• Maximum power output is 108 Watts (9 A)

10. 12V power input

12V power input

The DATAPixx3 is powered by a 12V input on the rear bottom right of the unit. Power supply and international adapter set are included with purchase.

When the DATAPixx3 is connected to power and powered OFF, the status LED on the front of the device will be illuminated in red. When the DATAPixx3 is connected and powered ON, the LED will be green.

Technical Specifications

• Power consumption: 50 Watts (DATAPixx3 only)

• Input voltage: 12 V DC

• International AC adaptor input: 90 VAC – 264 VAC (47 Hz – 63 Hz)

System Requirements

The following section outlines the software and hardware requirements for the PC and displays connected to the DATAPixx3.

VPixx Software Tools

VPixx Software Tools is a package of APIs and high-level software tools for use with VPixx products. It contains everything you need to connect to, configure and operate our devices from your experiment PC. It includes the following:

• LabMaestro, a program designed by VPixx Technologies for configuring VPixx hardware and designing/implementing experiments.

• Datapixx.mex, a library of commands for use with MATLAB/Psychtoolbox and VPixx products

• pypixxlib, a library of Python tools for VPixx products

The latest version of VPixx Software Tools can be downloaded directly from our website at any time. Support documentation, tutorials, and demos for all of our software tools can be found on our support site: Support Home

Supported operating systems

VPixx Software Tools are developed and supported under Windows, macOS and Linux (Ubuntu) operating systems. For an up-to-date list of supported OS versions visit Software Download & Information.

Recommendations for experiment PCs and graphics cards

We regularly receive questions about what experiment PC characteristics and graphics cards we recommend for use with our hardware. Generally speaking, most modern machines and GPUs (i.e., from the last 5 years) should be compatible with our devices. Unfortunately, we are not able to exhaustively test commercially available systems and make specific recommendations regarding makes/models.

If you are looking for a new experiment PC, VPixx offers a dual-boot Linux/Windows machine featuring a high-powered processor and GPU. Each unit is built and tested at our head office, and is guaranteed to work with VPixx products.

Recommendations for stimulus and console displays for use with the DATAPixx3

The DATAPixx3 supports all VPixx-manufactured displays as a stimulus display. In addition, third-party displays may be used, provided they support the following resolution/refresh:

Please note we do not support displays with a refresh rate >144 Hz or third-party displays with a native bit depth > 8 bits per colour. Adaptive refresh rate features, such as GSYNC and FREESYNC technologies, are not supported and should be disabled.

Recommendations for video adapters

Please use one of the following video protocols from your PC:

• DisplayPort

• DisplayPort mini/Thunderbolt

• USB-C to DisplayPort

We do not recommend converting from other video protocols (e.g., HDMI or VGA) as this can have unpredictable consequences for display behaviour.

If you are using the DATAPixx3 to drive a VPixx-manufactured display that uses Dual Link DVI input, we will supply you with a tested and vetted adapter for use with our displays.

Assembly and Installation

General recommendations

Ensure that the location where you place the device meets the following requirements:

• The DATAPixx3 vent is not blocked

• There is enough room behind the DATAPixx3 to allow for good airflow around the ports

• Keep the DATAPixx3 in a well-ventilated area, away from excessive light, heat, or moisture

• Use cables provided with your purchase rather than third-party cabling

• For rack-mount installations, refer to the associated user manual and use the optional bracket

• All DB25 cables (e.g.: analog or digital interface) should be screwed onto the DATAPixx3 during operation

• The maximum recommended length of DisplayPort cables for optimal performance is 6 ft or 1.8 meters. Please contact VPixx Technical Support for assistance if you require a longer cable.

Product assembly - Connecting to your PC

To connect your device to the experiment PC:

1. Connect your USB-B cable to the unit and an available port on your PC

2. Connect the DisplayPort cable to Video In 1 on the unit and your graphic card output on the PC

3. Connect the 12V power supply to the DATAPixx3 and an external power source

Product assembly - Connecting the stimulus and console display

Connect the stimulus display (main display used in the experiment) to Video Out 1 on the DATAPixx3. An optional secondary monitor can be connected to Video Out 2 (the console display) and will show a copy of the video to Video Out 1.

The console display is intended for the researcher to monitor the experiment's progress. Do not attempt to use it as part of your data collection apparatus; it shows a copy of the main video signal and thus may not preserve all the timing characteristics of the main stimulus display.

Product assembly - Connecting other systems

Connecting the DATAPixx3 to other systems is typically straightforward. Connect the designated cable to the relevant port on the rear of the unit. Depending on the connector type, you may need to screw the connector into place. For instructions for specific peripheral devices, see their respective hardware manuals.

Product Usage

The DATAPixx3 acts as an interface between your experiment PC and display, eye tracker and other peripherals. The exact layout of your system will depend on your research. Below is an example schematic of a DATAPixx3 research system:

The DATAPixx3 connects to your PC via USB/video and acts as the main interface for connected devices. Except for the PROPixx projector, which has a dedicated USB connection to the PC, the DATAPixx3 manages all hardware/display configuration and peripheral system control.

To interact with the DATAPixx3, you can use our MATLAB and Python command libraries or our LabMaestro software. Our documentation has many examples of how to communicate with our hardware, including collecting video-accurate timestamps, configuring automated TTL triggering, setting up audio playback, and more. See the Relevant Links section below for recommended guides to get started. In particular, we recommend our guide The Logic of VPixx Hardware Control, which provides an overview of the framework for the DATAPixx3 as a peripheral signal management system.

Test patterns are simple demonstrations of VPixx products. They are preloaded onto VPixx hardware and do not rely on your graphics card or experiment code. They are used to quickly visualize product features and validate system performance, independent of your PC.

To use test patterns, you must first install VPixx Software Tools on the PC connected to your VPixx hardware. Next, connect and power on your VPixx hardware. On Windows and Linux (VPixx software revision 1.9 and later), open the LabMaestro application and open a new or existing project. Right-click on the hardware in the Environment section of the Project Panel, and select Test Patterns from the menu. This will open the Test Pattern widget.

Only test patterns suitable for your selected device will appear in the widget. Note that test patterns for the PROPixx projector are found in the test pattern widget for the associated control unit (PROPixx Controller or DATAPixx3).

Each test pattern includes an explanation of the pattern and an example of expected behaviour. Some test patterns include options to adjust the pattern parameters. While a test pattern is enabled, your experiment display will be unresponsive to typical user behaviour (e.g., mouse clicks). Stop the test pattern to return to regular operation.

LED indicators and their meanings

The DATAPixx3 has several LED status indicators on the front right-hand side of the unit. See the table below for LED behaviours and their meanings.

Product Specifications

General specifications

• On-board memory: 2 GBytes for buffering I/O data

• Enclosure: steel, with 19’’ rack-mount hardware available

• Operating temperature: 0°C to 70°C

Pixel Mode

In Pixel Mode, your VPixx hardware sends automated digital TTL signals, aka ‘triggers,’ based on the colour of the top left pixel on the display. Triggers are locked to video frame onset with deterministic timing and microsecond precision. You can learn all about this feature in this guide: Sending Triggers with Pixel Mode. Use our Pixel Mode pixel value calculator to determine what pixel values you should use for your desired TTL output.

3D applications

This device has a VESA-standard 3D port, which can be used with the 3DPixx active shutter glasses kit (sold separately) to display 3D stimuli at a rate of 60 Hz/eye. There are several video modes available for formatting 3D stimuli with this system; for a comprehensive guide and demos, see this guide:

• 3D Stimulus Presentation with the VIEWPixx /3D

Analog subsystem

The analog subsystem of this device supports up to 16 concurrent analog inputs and 4 analog outputs. Analog cable are sold separately. For more details on how to use and configure analog channels on our hardware, see the following guides:

• Sending and Receiving Analog Signals with VPixx Hardware

Digital subsystem

The digital subsystem comprises a 24-channel digital input and a 24-channel digital output. These can be configured for recording and playback of TTL signals, respectively. Common digital inputs include our RESPONSEPixx button boxes and MRI triggers. Common outputs include custom event-based triggers, Pixel Mode triggers, and forwarding of button box inputs to third-party systems. For details on how to use the digital subsystem, including examples, see these guides:

• Sending Triggers with Pixel Mode

• Using Pixel Sync for Stimulus-Accurate Timing

• Forwarding RESPONSEPixx Button Activity to a Third-Party Receiver

• Record Response Times With a RESPONSEPixx Button Box

Audio subsystem

The audio subsystem includes a microphone in, an audio in, and an audio out. This device does not interact with your PC soundcard. Instead, you can configure the device hardware to record mic/audio inputs to the device’s onboard memory for later retrieval, load audio waveforms into device memory for playback with deterministic timing, or both. The advantage of this approach is that the device can operate independently of and in parallel with your experiment PC for improved timing and stimulus synchronization. For more details on how to use the audio system, see the following guides:

• The Logic of VPixx Hardware Control

Cleaning and Maintenance

The DATAPixx3 video I/O hub has a metal chassis. It can be cleaned with regular cleaning products or disinfectants. If you are using a spray, spray the product into a soft cloth and wipe down the device—do not directly spray the product on the device, especially near the ports.

Cables, power bars and plugs can be wiped down in the same manner. Avoid bending or folding fragile cables, particularly fibre optic cables, during cleaning.

To clean the interior of the ports, spray compressed air into the sockets to remove dust and debris.

As a best practice, we recommend power cycling this device (e.g., turning it off and on again) occasionally to ensure optimal operation.

Troubleshooting your Device

Below are some possible issues you can encounter when using the DATAPixx3.

Related Links

• The Logic of VPixx Hardware Control

• Sending Triggers with Pixel Mode

• Using Pixel Sync for Stimulus-Accurate Timing

• Sending and Receiving Analog Signals with VPixx Hardware

• DATAPixx3 Video Tour (youtube.com)

Compliance, Safety and Warranty Information

Click on the sections below to expand the relevant information.

Compliance Information

The VideoBahn interface on the DATAPixx3 uses a fibre optic module whose manufacturer provides a certificate of conformance for standard IEC 60825-1 Ed. 3 (2014)

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For the United States of America

This device complies with part 15 subpart B of FCC rules. Its operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.  This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15 subpart B of the FCC rules.

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For Canada

This Class A digital apparatus complies with Canadian ICES-003.

CISPR warning: This is a Class A product. In domestic environments this product may cause radio interference in which case the user may be required to take adequate measures.

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For European Countries

DECLARATION OF CONFORMITY

Manufacturer’s Name:                 VPixx Technologies Inc. Manufacturer’s Address:              630 Clairevue West suite 301 Saint-Bruno, Qc Canada, J3V 6B4

Product Name: DATAPixx3 Full and DATAPixx3 Lite Part Numbers:  VPX-DPX-1005C and VPX-DPX-1004A Product Options : All Application of Council Directive:
2014/30/EEC  2015/863/EU 2012/19/EU	Electromagnetic Compatibility directive Restriction of Hazardous Substances Directive Waste Electrical and Electronic Equipment directive
The following harmonized standards have been used:
EN 61326-1:2013 IEC CISPR 11 IEC 61000-3-2 IEC 61000-3-3 IEC 61000-4-2 IEC 61000-4-3 IEC 61000-4-4 IEC 61000-4-5  IEC 61000-4-6  IEC 61000-4-8 IEC 61000-4-11 IEC 60825-1 Ed. 3 (2014)	Electrical equipment for measurement, control and laboratory use. Radio frequency disturbance characteristics (Class A) Limits for harmonic current emissions (Class D) Limitation of voltage changes, voltage flicker (≤16A per phase) Electrostatic discharge immunity test (Level 2 contact, air) (Perf Criteria B) Radiated, radio-frequency, electromagnetic field immunity test (Level 2, Perf Criteria A) Electrical fast transient/burst immunity test (Level 2, Perf Criteria B) Surge immunity test (Level 2, Perf Criteria B) Immunity to conducted disturbances, induced by radio-frequency fields (Level 2, Perf Criteria A) Power frequency magnetic field immunity test (Level 2, Perf Criteria A) Voltage dips, short interruptions and voltage variations immunity tests (Perf Criteria B and  C) CLASS 1 LASER PRODUCT

SUPPLEMENTARY INFORMATION To remain CE compliant, only CE compliant parts should be used with this product. Maintaining CE compliance also requires proper cable and cabling techniques. VPixx Technologies will not retest systems or components that have been modified by customers. Signature:

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The following information is only for EU member states:

The mark shown to the left is in compliance with the Waste Electrical and Electronic Equipment directive 2012/19/EU (WEEE). The mark indicates the requirement NOT to dispose of the equipment as unsorted municipal waste.  For more information call VPixx Technologies Inc. or email us at support@vpixx.com

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Declaration of RoHS Compliance

This product has been designed and manufactured in compliance with Directive 2015/863/EU of the European Parliament and the Council on the restriction of the use of certain hazardous substances in electrical and electronic equipment (RoHS Directive).

Safety and Warnings

This device is intended solely for research purposes and is not suitable for medical applications or diagnostic use.

Product care

• Do not open the device. There are no user-serviceable parts inside.

• Use only the power cable provided.

• Ensure that the power outlet includes a ground connection, as this equipment MUST be grounded.

• Handle the power cable carefully and avoid sharp bends. Do not use a damaged power cable.

• Do not cover or obstruct the ventilation outlets or inlets.

• Do not expose the DATAPixx3 to rain or moisture, and do not place any liquids on its top surface.

• Ensure that the total ampere rating of the products connected to the AC outlet does not exceed the current rating of the electrical outlet, and that the total ampere rating of the products connected to the power cord does not exceed the rating of the power cord. Look on the power label to determine the ampere rating (Amps or A) for each device.

• For recommendations on cleaning this device, see the section on Cleaning and Maintenance.