EEG new computer lacks printer port for trigger sending

OS (e.g. Win10): Windows 10 Enterprise
PsychoPy version (e.g. 1.84.x): PsychoPy 2023.2.3
Standard Standalone? (y/n) Y
What are you trying to achieve?:

Trying to send triggers to from stimulus computer to acquisition computer (via Curry 7) using a Compumedics Neuroscan EEG system.

What did you try to make it work?:

Our old stimulus computer (32 bit machine) used with our NeuroScan EEG system has a printer port but we wanted to switch to a 64 bit machine to use PsychoPy. We brought in a new Dell computer (specs listed on this thread above) but it does not have a printer port. We have adapters in lab for standard USB 2.0 to printer port that we can use with existing Neuroscan cable and try but I’m concerned about timing and what port address to use in this case for PsychoPy? Alternative would be to get IT to mount a printer port to the machine?

USB-to-parallel port adapters (as well as USB-to-serial) have really poor timing. The issue is not the hardware – the hardware is plenty fast. The issue is the USB driver that comes with them. They tend to buffer data for efficiency, causing event markers that you send to sit in the buffer for a while (30+ milliseconds is not unusual).

If you don’t want to invest in something like c-pod (made by our company Cedrus) and you are using a desktop PC, another option is a parallel port adapter that plugs inside your PC. We tested one in the past and had very good timing with it.

Hello @habboud thanks for the reply. Could you provide an example link of the adapter you are referencing for comparison? I’m at a university so I can send in request and see if they’ll approve c pod if not go this route.

It’s been at least 10 years since we last looked at these adapter cards. Currently, there is only one lonely PC in our office that accepts such cards! Everything else is either laptops or Apple iMacs running Windows. Sorry that I can’t assist.

If you’re going to search, start by finding out what type of card your specific Dell computer accepts.

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Hi @habboud,

When using the c-pod for neuroscan and no printer port what does the c-pod actually connect to on the stimulus computer? USB? trying to figure out what the port-address (serial or p-port) would be for the psychopy stim computer if we go this route. I’m assuming from the photo it connects to the LPT cable from the neuroscan system, but what about stim side?


Yes, c-pod connects to the computer’s USB port.

If you are using our pyxid2 library, you do not need to deal with port addresses. The library provides a get_xid_devices() function that scans all available ports:

import pyxid2
import time

# get a list of all attached XID devices
devices = pyxid2.get_xid_devices()

The code above is from this sample.

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Hi habboud thanks for clarifying. I currently have the experiment set up as a loop where either a word or image (actual word or file path to image found in excel file) appears and corresponding triggers are set in the Excel document that is loaded in psychopy as trials so it appears on same line.

I can add code to my routine to use pyxid2 but I’m admittedly more novice with coding so do you have any advice or examples on how I would get triggers to read appropriately from the Excel file that has them all in row with the corresponding stimuli?

Thanks for your help. Looking forward to our c-pod arriving.

Alas, we can assist only with questions related to interfacing with our products.

We will be using your product. I just am not sure how to get PsychoPy to recognize it in the builder as an address (without coding expertise - if possible).

There is no address to specify. Please see this support page, Using c-pod with PsychoPy. If you still need support afterwards, feel free to email me directly so we can arrange for zoom meeting.