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Popular questions about hardware and software, answered. Includes a general troubleshooting guide for common problems encountered during setup and testing..

Table of Contents


This guide is a list of frequently asked questions related to our products, and answers to these questions. The sections below are divided into general topics: Sales, Hardware, Software and General Troubleshooting. The Hardware section include a few subcategories for device-specific questions.



The VPixx Online Classroom and Library (VOCAL) is a growing set of online projects and resources for vision scientists using our products. You can also find more details about our tools for research in our Application Guide, and in the User Manuals and Demos section of MyVPixx

Sales and Ordering Information

Where is VPixx located? Do you have distribution facilities in my country?

Our offices and manufacturing facilities are located just outside of Montreal, Canada. All orders are shipped from Canada.

If you are based in China, Taiwan, Korea, Japan or India, we work with distributors in these countries to facilitate import of our products. Please contact us at and we will put you in touch with the distributor for your region.

Do you ship to my country?

We ship worldwide, including to the Americas, Europe, Australia and the Middle East. For sanctioned countries listed on the Global Affairs Canada website, please contact us at to determine your eligibility.

If you are based in China, Taiwan, Korea, Japan or India, we work with distributors in these countries to facilitate import of our products. Please contact us at and we will put you in touch with our distributors.

How do I place an order?

If you are interested in our products, you can contact our team via our contact portal ( ) or to obtain an official quote. If you’re not sure what specific tools you need, our team of experienced staff scientists will be happy to provide you with a tailored consultation, either by video/phone call or email. These quotes are valid for 90 days from issue and include the cost of shipment to your institution.


Please contact us at for enquiries related to payment methods and payment terms.

When will my order be delivered?

Our official lead time is 45 days from when the purchase order is received, to when the item ships. Please allow for some additional time for shipping. Unfortunately, we cannot guarantee a specific delivery date.

Can you deliver by XX date?

We will ship your order within 45 days of receipt of the purchase order. However, once the order leaves our facility, we cannot predict or prevent delays due to shipping agents or customs.

If you have a specific deadline by which you need our products, please notify a VPixx associate as soon as possible. We will do our best to accommodate your deadline. If you have an extremely strict deadline (e.g., expiring funding), we recommend placing orders as early as feasible.

Do you charge taxes/VAT?

If you are based in Canada, we will charge taxes that apply to your province or territory. These taxes will be included in your quote.

If you are outside of Canada we cannot directly charge taxes on our products. The taxes on shipped goods will be determined by a customs agent, and charged by the shipping agent. VPixx cannot pay these charges on behalf of the customer. If your university or institution has tax-exempt status, we ask that you provide us with the required documents to be included in the shipment. Please speak with your institution’s purchasing office to find out the specific documents required for your region.

What is a SOA and why do I have to sign it?

SOA stands for “Sales Order Acknowledgment.” The SOA is a document created by VPixx which summarizes the order information. It includes the following details:


The SOA provides an opportunity for all parties to verify the terms of the sale. It does not supersede the purchase order, although it may contain information (such as the shipping contact) which does not appear on the official order. This is especially useful in situations where the purchase order does not contain a descriptive list of the purchased items, is in a different language, or there is a long delay between the initial communication about the purchased items and the order being placed.

Who is qualified to sign an SOA?

The researcher requesting the equipment, a trainee or administrator acting on their behalf, or a university purchasing agent are all qualified to sign the SOA.

Can I change the shipping address after the purchase order has been issued by my institution?

You can change the shipping address by sending us a revised purchase order. We can accept this revision up until the product is packed and labelled for shipping.

Can I use my university’s shipping agent or broker?

Yes, you can. Please inform the VPixx associate who is managing your quote if you wish to use your own shipping arrangements.

We will need to know if you plan to arrange your own pick up, which carrier you intend to use, and we will need contact information for your shipping agent. If you are planning to use a University Fedex account, we will manage the shipping and provide Fedex with your account number for invoicing.

Do you provide on-site installation and training?

VPixx Technologies is monitoring the COVID-19 global pandemic as it unfolds. Our team must adhere to government travel directives.


Our technical support staff are always happy to provide live remote installation support. Please contact for assistance.



What are the system requirements for VPixx hardware?

The short answer: our hardware is compatible with all recent major operating systems. We support:


If you need an out-of-the box solution that works, the dual boot Linux/Windows machine service is thoroughly tested and tweaked. It is the only complete system guaranteed to work with our devices and is backed by a 3-year manufacturer’s warranty.

What kind of graphics card do I need?


What is the difference between a “Lite” and a “Full” data acquisition system?


As of September 2023, all units sold by VPixx Technologies are equipped with the “Full” data acquisition system. If you would like to upgrade a legacy Lite system, please contact with your product serial code for pricing and details.

The following text refers to units sold prior to September 2023.


Please note that I/O cables are not included in the purchase of the core system; if you need standard or custom cables for data acquisition and output, please let our team know.

Can I upgrade my “Lite” data acquisition system to a “Full” system?


As of September 2023, all units sold by VPixx Technologies are equipped with the “Full” data acquisition system. If you would like to upgrade a legacy Lite system, please contact with your product serial code for pricing and details.

Can I drive VPixx hardware from multiple PCs?

Yes, you can. The easiest way to do this is to use a KVM switch. These switches allow you to toggle between different PC inputs to the same display hardware. We recommend the following models:

StarTech 2:1 KVM switch
StarTech 4:1 KVM switch

Can I use a video adapter if my graphics card does not have dual-link DVI output?

Almost all of our products require video in the form of dual-link DVI. The exception is the DATAPixx3 I/O hub, which uses DisplayPort. Below are our recommendations for converting to dual-link DVI from other video protocols.


VGA: Not recommended. Analog video protocols are notoriously difficult to digitize and can create all kinds of display artefacts, if they work at all.

Can I use multiple screens at the same time?

Best practice during data collection is to disable all secondary displays and only run the stimulus display. This reduces load on your graphics card and minimizes the risk of frame dropping and other latency issues associated with overtaxing your graphics processor.


The second option for driving a secondary display is to drive it directly from a second port on the graphics card. The effect this will have on the performance of the main display will vary from system to system. A powerful graphics card may be able to manage both displays without significant frame dropping. If you decide on this route, it is a VERY good idea to run some synchronization tests prior to data collection, to ensure you have a tolerable rate of frame dropping and you are not compromising your stimulus presentation.

I need to connect my VPixx hardware to another system via the I/O ports. Where do I start?

This response is focused on setting up hardware. For tips on how to set up triggers in software, please see our demos and our VOCAL guide to Pixel Mode. Pin assignment information can be found in your device user manual.


For more details, please contact our team of trained vision scientists at

How do I (re)calibrate my display? How often should I recalibrate?

Instructions for running our automated calibration routines for the VIEWPixx and VIEWPixx /3D CRT replacement monitors, and the PROPixx DLP projector, can be found on page 115 of our Product Application Guide [pdf].


We have found that our displays maintain luminance and chromaticity characteristics consistently for a long time. Your displays should not require re-calibration for about 5-10 years, depending on how heavily they are used. After 5 years you may wish to take occasional measurements to verify your displays are still within an acceptable range of luminance/white point.  

Is VPixx hardware rated for medical applications?

VPixx Technologies develops and manufactures research tools, which are not regulated for use as diagnostic or medical equipment. 


VPixx Technologies’ goal has always been to enable researchers to push the boundaries of what can be studied in vision research. Our products and tools are often developed by request, and in response to specific, pressing research questions. We have chosen to dedicate our efforts to this fast-paced development, rather than attempting to acquire medical ratings for our devices. 

How do I clean my VPixx devices and displays?

Cleaning recommendations for specific devices can be found in the documentation for that device


Does VPixx manufacture projection screens?

Yes! We manufacture a variety of screen sizes and shapes for tabletop, standalone and in-bore use.


We do not offer hard acrylic screens or roll-up screens.

What is the difference between a 2D and a 3D projection screen?

Screen material optimized for 3D has a silver/grey coating and preserves the clockwise and anticlockwise polarization of light for left- and right-eye images. This coating sacrifices a bit of image brightness, and has less uniform luminance across wide viewing angles. Screen material for 2D stimuli produces a brighter image and has a more uniform luminance distribution.


For rear projection, researchers must choose between 2D and 3D optimized screen materials. It is possible to show 2D images on a 3D screen, especially on smaller screens. Conversely, 2D material will scatter 3D polarization and is not compatible with 3D stimulus presentation.

Can I use a SHIELDPixx with a third-party projector?

The SHIELDPixx MRI shielding enclosure is designed specifically for in-room installations with the PROPixx MRI-safe projector. It is not sold as an independent unit and cannot be used with third-party projection systems. 

What is the gamma of the PROPixx?

The PROPixx uses DLP technology, which has an inherently linear gamma of 1.

My current PROPixx lens doesn’t work with my new research space. Can I change lenses?

Yes! If you are moving labs, or changing your testing layout, and your current lens does not support the distance/size requirements of the new space, you can purchase a new lens and install it on your current projector. Along with the new lens, we will provide you with instructions on how to swap your lenses out. The process takes less than 15 minutes.


Not sure what lens you need? You can check out our guide to PROPixx projection geometry, or contact our scientist team at

What is the lifespan of the PROPixx light source? Is it possible to replace it?

The PROPixx uses RGB LED light sources with a lifetime of approximately 60,000 hours. Even with heavy use, this light source should last decades. 

In the event the light source exceeds its lifetime and must be replaced, the unit can be shipped to VPixx Technologies for disassembly, LED chip replacement, and full factory calibration. If you require this service, please contact our technical support team ( for more details and a quote for the LED replacement costs.

I’d like to mount the PROPixx on a ceiling or wall bracket. Do you have recommendations?

We do not have specific recommendations for mounting brackets for the PROPixx. The PROPixx has three M4 mounting holes with a 0.7 mm pitch on the base for bolting the device to a ceiling or wall plate. Please see page 13 of the PROPixx user manual for spacing (measurements are in inches).


Once mounted, the PROPixx can be set to “ceiling mount” in PyPixx to invert the display.


Can I connect a RESPONSEPixx button box directly to my PC?

The RESPONSEPixx button boxes use a digital TTL triggering system and terminates in a DB-25 connector. These boxes are designed to work with the digital input port on our data acquisition systems, including the DATAPixx video I/O hubs, the VIEWPixx /3D and VIEWPixx CRT replacement monitors, and the PROPixx Controller. When paired with these systems, the RESPONSEPixx provides microsecond-precise measurements of button press/release times.


The precise sampling rate will depend on your particular experiment program and what is happening in your checking loop. It will absolutely be slower than the sampling rate of a digital input log running on separate, dedicated hardware. Depending on your experiment this may not be an issue, but it is certainly something to keep in mind when designing timing-sensitive research paradigms.

Can I get custom button colours, or a custom layout?

We can create custom button layouts according to your specifications. Please contact with your desired layout (including spacing and number of buttons) or colour requests.  

Do you have a joystick or gamepad option available?

We do not. However, the ‘full’ versions of our data acquisition systems are capable of receiving analog signals from third party devices, such as joysticks.

VIEWPixx /EEG, VIEWPixx and VIEWPixx /3D

What is a “CRT replacement monitor?”

Our VIEWPixx series of monitors are LCD displays that use modern-day technology, but have custom hardware to mimic the highly desirable temporal properties of old-fashioned CRT displays. To find out more, see our/wiki/spaces/Vocal/pages/9666597.

What is the difference between the three VIEWPixx monitors?

There’s an entire VOCAL guide that explains this in detail: /wiki/spaces/Vocal/pages/9666597 You can jump to the end for a summary table that provides a side-by-side comparison.

What is the gamma of your VIEWPixx displays?

The exact number varies slightly from unit to unit. A good rule of thumb for most LCD monitors, including our VIEWPixx displays, is a gamma of 2.2.

If your experiment requires extremely precise gamma correction, the best method to determine your display-specific gamma is to /wiki/spaces/Vocal/pages/13467704 with a spectrophotometer or colorimeter.

I want to mount my monitor on a wall bracket or rolling stand. What are your recommendations?

All three of our VIEWPixx monitors use the following mounting standards:


At the office, we mount our test displays on mobile relay racks like these, along with a fixed TV wall mount bracket similar to these. This wall mount is large enough to be fixed on the rack and has adjustable brackets that can be used to attach the monitor. This solution works well for a mobile display.

Can I run my display at 60 Hz during an experiment? Why is there a flashing red square in the corner?

The VIEWPixx series of monitors are designed to run at 100 Hz or 120 Hz. When the video signal drops below 100 Hz, the display automatically implements an internal frame buffer and begins resampling the video signal to maintain a screen refresh rate of 120 Hz. A flashing red square will appear in the top left corner of the screen whenever your display is in resampling mode. 

This resampling mode can cause problems for timing-sensitive experiment tools. For this reason, we do not recommend using 60 Hz in experiments where timing is critical for stimulus presentation or data collection. 

Do the VIEWPixx and VIEWPixx /3D run at high bit depth by default? How do I enable these modes?

The VIEWPixx can display up to 12 bits per colour (bpc), and the VIEWPixx /3D can display up to 10 bpc. By default, both displays will show 8 bpc, high definition full-colour video at 120 Hz. This is the maximum possible bandwidth supported by a dual-link DVI protocol.

In order to show video at higher bit depths, it is necessary to make a tradeoff to free up bandwidth for the additional bits. There is a guide to our high bit depth modes here.


Where can I find the most recent software release information?

You can find all details and documentation related to our releases at:

MyVPixx > What’s New

How can I find out my current software/firmware revision?

In PyPixx, navigate to System > About us. You will see a list of software and firmware revisions below the information about our company.

Don’t see this content? You may be using an older version of our tools. You can also get this information in the VPutil command-line software using ‘rev’.

How do I check for software and firmware updates?

If you have a recent copy of our software tools, you can check for software and firmware updates in the PyPixx program by navigating to:


Installing MATLAB .mex files
Installing pypixxlib in Python

How do I install VPixx Software Tools?

Your VPixx purchase should include a USB stick containing a copy of VPixx Software Tools. This includes all programs and software packages needed to run our devices. There is one set of Software Tools that covers all VPixx hardware.


Installing MATLAB .mex files
Installing pypixxlib in Python

What is PyPixx?

PyPixx is our standalone software utility that allows you to:


PyPixx is included in our VPixx Software Tools.

What is VPutil?

VPutil is a command-line tool that is included with our VPixx Software Tools. It allows you to change basic settings on your VPixx device, install firmware updates, manually read the device register for diagnostic purposes, and run several demos to test hardware performance.

Do you support MATLAB/Octave?

Our free software tools include an API specifically designed to work with MATLAB/Octave and Psychtoolbox


Please note we no longer support 32-bit versions of MATLAB.

Do you support PsychoPy?

Our free software tools include a Python API that allows users to drive VPixx hardware via custom Python scripts.


Not sure where to start? We have a VOCAL with tips and examples /wiki/spaces/Vocal/pages/62849025

Do you support Python IDEs (PyCharm, Spyder, etc?)

Absolutely. Our Python API comes in two flavours. Pypixxlib uses an object-oriented approach, while the libdpx wrapper permits more sequential programming. Which strategy you opt for is a matter of personal preference. Throughout several VOCAL guides we provide examples of both types of Python code.

For more details on how to install our Python tools, click here.

Do you support Presentation?

We do not currently provide software support for NeuroBehavioral Systems’ Presentation software. However, it is possible to configure our hardware to communicate with the Presentation PC via the parallel port and our DB25 digital output. 


Presentation does have MATLAB extension that allows users to run MATLAB scripts. As of April 2021, this extension only supports 32-bit MATLAB (r2015 and earlier). As soon as the extension supports 64-bit MATLAB, in theory it will be possible to use our full MATLAB API in Presentation.

Do you support E-Prime?

It is possible to use our MATLAB/Psychtoolbox tools in E-Prime by running a MATLAB server. You will need a copy of MATLAB and administrator privileges to do this.

Full instructions for how to use our devices in E-Prime can be found on page 128 of the VPixx Application Guide [pdf].

Do you support __________?

In a lot of cases, if a piece of software has some kind of extension or tool for running MATLAB or Python code, there is a chance our API can be integrated into it. 


Not sure whether integration might be possible with your existing experiment pipeline? Reach out to our technical support team at and we will help you investigate.



VPixx hardware is plugged in and powered on, but is not detected by software

If you recently crashed out of an experiment program, your VPixx Device Server may have frozen. You can restart it via the following methods:


If this does not resolve the issue, please contact technical support (

Console display (video out 2) shows an “Out of Range” error

If the console monitor is a make and model recommended by the VPixx team, or if it was purchased directly from us, this error is normal and should disappear on its own after about a minute. After this your screen will work normally.

If the message persists for several minutes, or is accompanied by other screen artefacts (like tearing or flickering), your monitor may not be suitable for use as a console. Please ensure it is set to 1920 x 1080 @ 120 Hz. If this does not resolve the issue, you may need to use a different monitor.

VPixx hardware is detected, but video is not showing or is showing poor quality video

You may be sending video at an unsupported resolution or refresh rate. Check your graphics card and display settings and make sure they are set to one of our specified resolutions and refresh rates. Please also ensure your video cable is dual-link DVI, not single-link.


If your desired resolution does not appear in your display settings, you can specify the display EDID in PyPixx in the Configuration widget. There are two ‘slots’ available, which you can set to two of your preferred settings. You may need to restart your VPixx device for the new EDIDs to take effect.

PROPixx image is flickering

This is typically a sign that your video signal is being attenuated. This is common with longer cables. If you have a booster (small box connected to the video cable, located near the projector), you can try adjusting the dial on the side until you achieve a stable image. If you do NOT have a booster, you may want to try a different, shorter video cable.

VIEWPixx monitor has a flashing red square in the top corner

The flashing red square in the top corner of the display indicates that your video frame rate has dropped below 100 Hz (usually to 60 Hz). When this happens, the VIEWPixx goes into “resampling” mode and repeats incoming video frames in order to continue displaying images at a rate of 120 Hz.


If you don’t see an option for 1920 x 1080 @ 120 Hz, it may be that you are using a single-link DVI cable, not dual-link. In that case you may need to swap cables and restart the monitor to be able to change the display settings.


Invalid MEX-file or Datapixx(‘Open’) fail in MATLAB

This error is usually caused by an outdated MATLAB executable (.mex file) in your Psychtoolbox folder. This file must be manually updated each time you update VPixx Software Tools. Please follow the steps here. 

MATLAB -1010 error or MATLAB script freezes and crashes

There are many possible reasons for this error, but common culprits are the following commands:


If these sync functions are not relevant or you want to get around them for debugging purposes, both functions have a timeout argument that can be set to 1-2 frames to cause them to execute right away and prevent queuing subsequent commands. Doing this renders their sync function useless and will definitely mess up any timing or synchronization that depends on them. We do not recommend doing this during data collection.


“Module not found” / code unable to find pypixxlib

As a first step, please follow the instructions here and install your pypixxlib file in the appropriate Python folder. This is usually something like:


If you are using the PsychoPy builder, you can add locations to your path by navigating to File-> Preferences -> General and clicking on the little square with the ‘…’ from the row labelled “paths”. 

Pixel Mode triggers not working properly (in PsychoPy)

Pixel mode is a method of sending automated TTL triggers, with timing locked to the onset of your visual stimuli. This is an easy and efficient method for sending triggers to external systems to synchronize them with display behaviour.