Installing USB Driver for Mac OS

Important: Which Driver to Choose

There are two different USB drivers available for the Mac:

VCP, or Virtual COM Port. When installed, the driver makes macOS think that your Mac has a real serial port. This enables a wide range of software to work since a lot of it was written to support serial ports. Timing resolution is estimated to be about 5-6 milliseconds.
D2xx: This driver is specific to the USB interface chips (made by FTDI) that are found in our response pads and in StimTracker. But it offers much improved timing: a fixed 2 millisecond delay with zero milliseconds jitter.

On macOS, these two drivers are unfortunately mutually exclusive: they cannot both be installed at the same time. The choice depends on which application software you want to use:

Use D2xx driver with SuperLab 6 or later, SuperLab X6, Xidon 2, PsychoPy, pyxid2 library, and our C++ library.
Use VCP driver with all other software, e.g. SuperLab version 5 or earlier, version 1 of the XID libraries, and E-Prime.

Installing a VCP Driver

Skip this section if you want to install the D2xx driver.

For macOS 10.11 “El Capitan” or Later

Starting with macOS 10.11, Apple started providing its own compatible USB VCP driver. You don’t need to install anything. If SuperLab 5 (or other software you use) is capable of communicating with the response pad, then you are set.

For macOS 10.10 “Yosemite” or Earlier

See the instructions on this support note intended for the older RB-x40 response pads; it applies to Riponda as well.

Installing a D2xx Driver

Skip this section if you want to install the VCP driver.

The D2xx driver is included with the software that’s listed above, e.g. SuperLab 6, so there is no need to install it. However, the D2xx and VCP drivers cannot coexist. Even if you have not explicitly installed the VCP driver, Apple started including its own compatible VCP driver with macOS 10.9 “Mavericks”, and a pretty good one with macOS 10.11 “El Capitan” and later. FTDI provides a tool named “D2xxHelper” to take care of suppressing the VCP driver. You can find it on this web page:

Click on the D2xxHelper link in the Comments column of the table to download it
Run D2xxHelper
Restart your Mac

In certain situations, installing D2xxHelper may not be enough and a VCP driver must be explicitly deleted. To do so, run the Terminal program, found in your Applications > Utilities folder, and type:

‍ sudo rm –r /Library/Extensions/FTDIUSBSerialDriver.kext

Then restart your Mac.

Switching Between VCP and D2xx Drivers

You might find yourself in a situation where you need to switch between VCP and D2xx drivers. The D2xxHelper that’s mentioned above takes care of “muting” the VCP drivers but without deleting them. So switching between the two types of drivers consists of enabling or disabling D2xxHelper. The most efficient way to do so is by using the Terminal program, found in your Applications > Utilities folder.

To delete D2xxHelper, type in Terminal: