Response box USB serial cable

[Paul Gr]

Dear Wiltrud,

Most USB-to-RS232 interface cables will work right out of the box, but you
should be aware of the following: Although USB hardware supports much higher
data throughput rates than RS232 (i.e. can transfer more bytes per second),
the USB-protocol consists of a rather complex driver hierarchy, which could
introduce a reasonably amount of delay’s during data transmission. So, USB
will influence the accuracy of response times measured by E-Prime. (I
haven’t measured those timings yet, but perhaps PST is willing to give you
some details.)

When accurate response times are not required, then you can safely use a
USB-serial cable to connect the serial box. However, while installing the
driver for the virtual COM-port, windows will assign the first available
(unused) COM-port to your cable. You should check the assigned port number
(Control panel> System-> Hardware->COM & LPT ports) and make sure it
corresponds to the settings in your EPrime script. (I think EPrime only
supports COM1 to COM4). Also notice that windows will assign a different COM
port when you switch to another USB port. You might have to manually
configure all the available ports to have identical port numbers.

Paul Groot
Vrije Universiteit Amsterdam
The Netherlands

>From: Wiltrud Fassbinder <wifst3 at pitt.edu>
>To: eprime at mail.talkbank.org
>Subject: Response box USB serial cable
>Date: Sat, 29 Jan 2005 17:31:46 -0500
>
>I have a computer available that does not have a serial port, and I want to
>use the E-prime response box. So I thought I could use a USB-serial cable
>to connect it. Is there anything I should be watching out for, or will any
>cable work?
>
>Thanks again,
>Wiltrud
>
>Wiltrud Fassbinder
>Communication Science and Disorder
>University of Pittsburgh
>
>
>

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