Receiving TTL Signals from 2 Response Boxes (case 13508)

I am running an experiment through DirectRT to gather response time data from participants' true/false responses. When an item is presented, I have participants respond using a true/false scale on one response box (they can only select key 2 or 8). After the participant has selected his/her answer, I would like to have the participant press one key (key "5") on another response box to advance to the next item. I have specified in my Excel document that for each item that requires a true/false response, only responses of "2" or "8" from port 7718 should be accepted (syntax: "rt:2,8,(7718)"). I also specify when only key 4 can be pressed on the other response box ("rt:5,(7725)"). When I run the experiment in DirectRT, however, the program registers key presses from either response box. E.g., When a response is restricted to the 5 key, I can only press 5 to advance, but I can do so on either response box. I am unsure what I am doing wrong or if DirectRT is incapable of distinguishing signals from 2 identical response boxes.

Could you please upload a copy of your input file? It may be easier to see any problems if I can take a look at the entire file.

Hi Jason,

Here is my input file.

We should make sure that your computer is picking up the signals from each of your boxes at only the intended port. Oepn the IO Test application (if you used the default settings when installing DirectRT, it should be located at C:\DirectRT\Utilities\TTL. The folder also has a readme file with instructions).


Make sure that the IO Test is only showing results for one button box through the port assigned to it and nothing from the other box. This way we can limit the problem to the hardware or whether it is something with the software.


Also, exactly what kind of button boxes are you using? Did you purchase them from Empirisoft? Just curious.

Hi Jason,

When I enter port number 7718 or 7725, under "Monitor," it reads "Port XXXX = 255" for both port numbers entered. When I change the byte value sent, the Monitor still reads = 255, again, for both port numbers.

The response boxes were purchased from Empirisoft. We recently had them updated (within the past 4 months).




[QUOTE=jason_reed;20473]We should make sure that your computer is picking up the signals from each of your boxes at only the intended port. Oepn the IO Test application (if you used the default settings when installing DirectRT, it should be located at C:\DirectRT\Utilities\TTL. The folder also has a readme file with instructions).


Make sure that the IO Test is only showing results for one button box through the port assigned to it and nothing from the other box. This way we can limit the problem to the hardware or whether it is something with the software.


Also, exactly what kind of button boxes are you using? Did you purchase them from Empirisoft? Just curious.[/QUOTE]

Where did you get the port addresses of 7718 and 7725? How are you connecting the external devices to the computer (i.e., a USB port, a parallel port)?

I retrieved the port numbers by going into the device manager, locating the two response boxes under the USB device section, and converting the last four digit name of the devices from hexadecimal to decimal. The response boxes are both plugged into USB ports.

I talked with our hardware area and they said it's more than likely that the response boxes you are using are not set up to send nor receive ttl signals. They function just like two other keyboards running in parallel. However, to confirm that, we would appreciate it if you could send a picture of any label on the bottom of the box to [email]service@empirisoft.com[/email], please include "case 13508" in the subject line of any such email.


Without getting into to too much detail, the reason you saw signals in the IOTest using the response boxes is because DirectRT still allows for any keypresses defined as ttl signals in an input file to also be entered as keypresses on any keyboard. For more detail, see "Receive a TTL signal on the following DirectRT manaual page: [url]http://www.empirisoft.com/directrt/help/directrt_samples_of13_ttl_signals.htm[/url].


Finally, I did want to let you know that what you were trying to accomplish in your original post would be possible if you had external devices with ttl capabilities. However, any keyboard also hooked up to that computer would also be capable of entering input, so you would need to be aware of that.

Hi Jason- Thanks for your responses. Is there any way to set-up the response boxes so they can send & receive TTL signals?