# Parallel Port Out Component¶

This component allows you to send triggers to a parallel port or to a LabJack device.

An example usage would be in EEG experiments to set the port to 0 when no stimuli are present and then set it to an identifier value for each stimulus synchronised to the start/stop of that stimulus. In that case you might set the Start data to be \$ID (with ID being a column in your conditions file) and set the Stop Data to be 0.

## Properties¶

Namestring

Everything in a PsychoPy experiment needs a unique name. The name should contain only letters, numbers and underscores (no punctuation marks or spaces).

Start :

The time that the stimulus should first appear. See Defining the onset/duration of components for details.

Stop :

Governs the duration for which the stimulus is presented. See Defining the onset/duration of components for details.

You need to know the address of the parallel port you wish to write to. The options that appear in this drop-down list are determined by the application preferences. You can add your particular port there if you prefer.

Start data0-255

When the start time/condition occurs this value will be sent to the parallel port. The value is given as a byte (a value from 0-255) controlling the 8 data pins of the parallel port.

Stop data0-255

As with start data but sent at the end of the period.

Sync to screenboolean

If true then the parallel port will be sent synchronised to the next screen refresh, which is ideal if it should indicate the onset of a visual stimulus. If set to False then the data will be set on the parallel port immediately.

API reference for iolab