Inquisit can communicate with external hardware such as fMRI, EEG, and Eye Tracker measurement systems via TTL signals sent via parallel port. Inquisit supports parallel port communication on both Mac and Windows computers. Inquisit's Parallel Port Monitor provides a handy tool for testing whether parallel port signal values are properly sent and received.
The Parallel Port Monitor tool can be launched by selecting the "Parallel Port Monitor..." command from Inquisit's "Tool" menu.
The Parallel Port Monitor tool allows you to send TTL signals through the parallel port of your choice, as well as monitor incoming TTL signals send from external devices. The parallel port can be useful for testing what kinds of TTL signals are sent or recognized by external devices such as EEGs amplifiers.
Inquisit recognizes TTL input to the Status and Data registers. When the "Receive" button is pressed, the Parallel Port Monitor tool displays both the byte value of the current input TTL signal as well as the high/low status of each individual pin. A checked box indicates high; unchecked indicates low.
Inquisit can send TTL input to the Data or Control registers. To send a signal, check the box for pin that should be high, then press the "Send" button. The corresponding pins will be set high or low and will remain in that state until another signal is sent.
The Parallel Port monitor also supports logging of parallel port input signals over time. To achieve maximum timing resolution, the logging tool boosts it's thread and process priorities and polls the parallel port state, logging the time of any changes. Results are saved in tab-delimited format that can be loaded into Inquisit and other data analysis tools such as Excel, SPSS, etc.
To log parallel port port input, simply click the Log... button on the Parallel Port Monitor. To start recording immediately, press the Record button. You can define a parallel port pin/bit as a trigger so that recording will start when the value of the selected bit transitions to high (bit value 1). The logging tool also enables you to specify the path of the log data file and the duration of time for signals to be logged.
Although parallel ports have long been sole province of Windows-based PCs, Inquisit extends support to the Mac OS X operating system. A parallel port can be connected to to your Mac Pro, Macbook Pro, or iMac, using Mac's Thunderbolt connector protocal. Specifically, a ExpressCard PCIe parallel port card can be connected to a Thunderbolt to PCIe adapter (e.g. Sonnet Echo Pro ExpressCard PCIe 2.0 Thundebolt Adapter), which can then be plugged into a Mac's Thunderbolt port. Additionally, a standard PCI or PCIe parallel port card can be plugged in directly to the PCI or PCIe slot on a Mac Pro's motherboard.
Importantly, Inquisit is compatible with single function parallel port cards only. Multi-function cards such as those with multiple parallel ports or a mix of parallel and serial ports are not supported.