Usually, a study participant is viewing stimuli on a computer screen while their EEG is recorded through the hardware provided by a manufacturer. To later synchronize the EEG data to stimuli, an experimenter will send so-called 'markers' from the stimulation computer to the EEG hardware so that the markers are encoded in realtime together with the EEG data.
Why do most manufacturers use the old-fashioned parallel port for that?
I know, that the parallel port allows for a parallel transmission of up to 8 bits (i.e., 255 possible marker values and one '0' marker to indicate 'no marker') ... however, while that is a clear advantage, it comes at the cost of using a legacy port that is not available on modern computers.
Couldn't we just use a USB port to send data serially (in smaller bit packages) ... and then join these bits to a byte (8bits) to get the same number of possible markers? USB would in theory be fast enough to even compensate for the extra time needed to 'buffer' single bits and then encoding them as a byte.
Am I getting something wrong?
Why is the parallel port still so prevalent for this specific application (EEG)?