How to send a trigger signal to a channel for a parallel connection

Psychopy version: 2021.1.4-win64 system
Windows system: win10
Hello, everyone,

I want to send a pulse signal to only one channel in the EEG system(such as international 10-20 EEG system,F3 channel), and the communication between the EEG system and Psychopy is via a 25-pin parallel port cable. How do I write the code for this in code Interface?

I am very eager to hear your suggestions and ideas, thank you very much!
Best wishes to all.

Hi There,

Are you able to send a trigger using the parallel port component in builder? What is your EEG system?


Hello Becca,

Yes, I tested it and it doesn’t work either, my EEG system is 256- channel Nihon Kohden EEG system.


Hi Melody,

Could you describe a little more how it “doesn’t work”, is there an error message or is it that it doesn’t behave as you expect?


Take a look at this post on stackoverflow: python - PsychoPy sending triggers on 64bit OS - Stack Overflow

The PsychoPy code is outdated due to the parallel port component that @Becca mentioned but using the LPT Test Utility should get you on the right track with respect to troubleshooting and finding the correct parallel port address.


There is no error message, the problem is that the marker does not appear on the EEG.Fortunately, I have found the reason: the parallel port socket of the computer used to run the experimental program was not available and could not send the pulse signal.

Anyway, thank you very much for your kind reply and for taking the time and effort to help me solve my problem.I sincerely and wholeheartedly wish you the best of luck in the future.



First of all, I am very happy to receive your kind advice, I am glad that I have mastered a way to send pulse signals in Psychopy through the Poster you gave me, secondly, I am lucky that my problem has been solved, anyway thank you very much for your time and effort to give me advice, you are a very kind and nice person.

Best wishes to you.

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Dear Melody,
I am trying to send a trigger signal from a laptop to a Nihon Kohden EEG channel. How did you get it to work? Most of Nihon Kohden EEG seems to be designed to output signals, but none to input signals. I was going to use a sound trigger to make a mark on the EEG.
Any tips?

Hello, kate

This is based on the computer port you present the experimental procedures and the port of the photoelectric system, and the two ports are divided into parallel and serial ports, so you need to determine the type of Nihon Kohden EEG system port and computer port you need to use.

Our Nihon Kohden EEG is parallel port, and the computer used is a desktop computer, is also parallel port.The trigger signal is connected to the computer and EEG system through a parallel port adapter cable, As for the specific how to send can be referred to here: psychopy.parallel - functions for interacting with the parallel port — PsychoPy v2022.1.2

About how to send a trigger signal with a laptop, because Generally, all commercially available laptops are serial port, And as we know the parallel port receiving the signal is unable to recognize the signal sent from the serial port, so you should need a serial to parallel port adapter or adapter box to send a trigger signal between EEG system and your laptop computer. Hope it can help you!