It doesn't matter which experiment generator you use to run your computer-based psychology experiments the Black Box ToolKit TTL to USB Keys Module helps with receiving basic TTL event marks as standard keyboard key presses or keystrokes.

Plug into a USB port on your PC and our TTL to USB Keys Module will appear as a second USB keyboard.

TTL to USB keys module pricing.

TTL to USB keys module key features

Designed as a simple and easy to use way to get TTL event marks into your software, the TTL to USB Keys Module allows you to check for key presses, or key strokes, that represent a TTL event trigger from your equipment, e.g. a sync pulse in fMRI, EEG event trigger, Eye tracker Area of Interest (AOI) etc.

Plug into a USB port on your PC and our TTL to USB Keys Module will appear as a second USB keyboard. Works out of the box with experiment generators like E-Prime, SuperLab, Presentation, Inquisit, PsychoPy or any other software that can work with a standard USB keyboard. When triggering from MRI, EEG, ERP, MEG systems simply wait for a pulse that has been converted to a key press.

Best of all our TTL to USB keys event marking modules can be used with any web-based, or web browser hosted, experiment to read TTL triggers from your own equipment. Works with sandboxed Psychology experiment delivery platforms such as Gorilla, Pavlovia, Labvanced, PsyToolkit, jsPsych, OSWeb, Psychstudio and Testable or any other system that can accept keyboard keystrokes.

All TTL to USB Keys modules ship with a USB host lead. An optional breakout board enables you to wire your own cables before making them permanent.

*Remember although our TTL to USB Keys Modules hardware is millisecond accurate and helps you utilize simple keyboard keystroke event marks in your experiments it cannot automatically correct for any mistimings that are inherent within the experiment generator or other hardware you use.

For example, if your experiment generator does not check for keyboard presses, or keystrokes, in a timely fashion because your OS intervenes, or an anti-virus check runs, your event marks will remain inaccurate regardless of the quality of the event marking device. What | Why | How

For self-validation you should independently check the accuracy and consistency of your experiment generators presentation and response event marking with a Black Box ToolKit v3 together with a BBTK TTL to USB Keys Module.

To independently TTL event mark stimuli and responses with sub-millisecond accuracy you should use our mBBTK v2. The unique mBBTK v2 takes over all timing and event marking duties from any experiment generator so you can be 100% sure of your presentation, synchronization, response timings and event marks.

Key features

  • 10 Digital +5 V TTL Input Lines
  • TTL Input Lines configured as:
    • 8 bit port on 25-way D female connector
    • 2 bit port on 2.5mm stereo connector
  • Change detection on TTL Input lines
  • Three modes of operation:
    • Mode 1: Assigned single key pressed when TTL line on/high and released when off/low
    • Mode 2: Assigned single key pressed/released when line on/high. Assigned single key pressed/released when line off/low. One key action per line change
    • Mode 3: Hexadecimal or Decimal number typed that represents TTL input status
  • Buffer overflow flag
  • USB HID transmit frequency configurable to ensure compatibility with non-compliant hardware
  • Works out of the box with PCs/Macs/Linux – fully plug in & play
  • Appears as a standard USB HID keyboard
  • Compatible with all Psychology experiment generators, e.g. E-Prime, SuperLab, Presentation, Inquisit, DMDX, ERTS, DirectRT, PsyScope, PsychoPy, OpenSesame etc
  • Works with any software that can accept key presses from a standard keyboard
  • Comes complete with our own key mapping and configuration software
  • Small and unobtrusive – Dimensions: 67.1mm x 28.2mm x 67.1mm (WHD)
  • Button to configure mode of operation
  • LED indicators for mode selection
  • Full-speed USB 2.0 (compatible with USB 3.0)
  • Scans the TTL port for changes every millisecond
  • Millisecond accurate TTL event marking in Mode 1*
  • Platforms supported:
    • Microsoft Windows XP SP3, Vista SP2 (32/64), Windows 7 SP1 (32/64), Windows 8 (32/64), Windows 10 (32/64), Windows 11 (64 bit)
    • macOS / iOS#
    • Linux#
    • Android#
#BBTK Microsoft Windows software Apps not supported directly. USB Keyboard HID natively supported via Plug and Play (PnP).

Example usage

Using the BBTK USB TLL event marking module is easy. Any software that can accept standard keystrokes from a USB keyboard can accept TTL event marks as they are simply typed as USB HID keystrokes as if they had been typed on a standard keyboard. For example, TTL input line 1 going high would type a number "1" and when line 1 goes low the key would be released. Whilst TTL line 1 was high, or on/active, the keystroke would be held down as if you had kept a key pressed down on a keyboard. This enables you to measure duration. The TTL to Keys Module can also be used with other Black Box ToolKit products. For example, a BBTK v3 or mBBTK v2 could trigger a TTL signal when an on-screen stimuli was detected resulting in a keyboard keystroke, e.g. a "1" when line 1 was active.

Breakout board

A breakout board lets you quickly and easily connect individual TTL lines before making a permanent connection.


Input Pins 2~9 shown in GREEN correspond to TTL Lines 1~8. Pin 25 is ground.

Configuration utility

Configuration software lets you set default mode of operation and other user configurable options.

Technical specifications

  • ABS plastic enclosure – Dimensions: 67.1mm x 28.2mm x 67.1mm (WHD)
  • Full-speed USB 2.0 (compatible with USB 3.0)
  • 1x 25-way female D connector for connecting 8x TTL output lines from your equipment. Plus 1x GND pin
  • 1x 2.5mm stereo socket for connecting 2x TTL output lines from your equipment. Plus 1x GND
  • Appears to the host PC/Mac/Linux system as a standard USB HID keyboard
  • Connects to the host PC via standard USB type A to B lead
  • Fully updatable firmware - 32K flash RAM (100,000 Erase/Write Cycles)
  • Supplied with configuration software for Windows XP, Vista, Win 7, Win 8/8.1 and Win 10
  • Three user selectable modes of operation via button on rear of unit
  • Checks for a TTL event mark or trigger event 1,000 times a second (1KHz sampling rate)
  •  Maximum frequency of changes on the TTL port: (assuming default USB HID setting of 1mS)#
    • Mode 1: 1000Hz
    • Mode 2: 500Hz
    • Mode 3: 250Hz for Hex or 166Hz Dec
#Dependent on specific USB subsystem, USB HID setting in the configuration app and load on the TTL port.

*Remember although our TTL to keys USB modules are millisecond accurate they can't automatically correct for any mistimings that are inherent within the experiment generator you use.

Unless otherwise labelled, all products offered for sale by The Black Box ToolKit Ltd are for academic study and/or research use only.

Who are we

Founded in 2003 by a team of psychologists, software experts and electronic engineers we are dedicated to improving the millisecond timing accuracy and experimental rigor of researchers in the behavioral and brain sciences.

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