FAQs

Question: Is it really necessary to match the impedance of the electrodes to the TDT headstage?

Answer: It is true that the impedance of the electrode should always be much less than the impedance of the headstage in order to have a good signal-to-noise ratio (SNR). However, the TDT low and high impedance headstages both have very high input impedances that are set specifically to record a high SNR only with an electrode whose impedance is in the specified range for that particular headstage. See the technical specifications page for your headstage to find out the acceptable impedance range.

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Question: Why do all zeros get loaded to the target buffer when using OpenDeveloper commands “WriteTargetV” and “WriteTarget”?

Answer: Unlike ActiveX commands that allow you to specify the data type to be loaded, the OpenDeveloper methods WriteTargetV and WriteTarget expect any data to be converted to type “single”. In MATLAB, convert your data using the "single" command.

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Question: Why do I only see signals from channels 1-4 and 17-20 even if I am acquiring data from 32 channels using 2 preamplifiers?

Answer: By default, the TDT preamplifier is set to acquire from 4 channels. To operate the preamplifier in 16-channel mode, one needs to connect pins 17 and 18 together. Note: this connection is automatically made when connecting the preamplifier to a TDT 16-channel headstage.

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Question: Why am I having problems connecting to or passing a transfer test with my TDT rack when using the USB interface?

Answer: There are two very common problems when using the USB interface. The first involves a mismatch between the USB version on the PC and the version on the TDT rack. When a TDT rack is using USB2.0 modules, the PC must also have USB2.0. The opposite setup (USB2.0 on the PC and USB1.1 on the TDT rack) should be compatible.

Also, racks will not work together if there is some combination of USB1.1 and USB2.0 modules on the TDT racks. If you are not sure what USB ports are on your PC then you can 1) check the PC manual or 2) assume that it is probably 2.0 if the PC was purchased new within the last 3 years.

USB version	TDT Part Numbers
1.1	UZ1, UB4
2.0	UZ2, UB2

The other common problem with the USB interface concerns installing the hardware. When first connecting the rack to a PC or even to a new USB port on the PC, a windows message will open saying that the PC has found new hardware. If the TDT Drivers are installed, and ONLY if they are installed, then it is OK to search for the appropriate drivers (usually answer: Yes, only this time). The computer will prompt the user through several windows and then the installation will appear to be complete. A moment later, another Found New Hardware message will appear. It is absolutely necessary to install the hardware as many times as this windows message appears. It may be necessary to install the hardware many different times, depending on the specific hardware setup.

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This article includes just a sample of the information you’ll find in the Frequently Asked Questions section of our Website. Please see the Support page on the TDT Website for links to more FAQs on installation issues, OpenEx, RPvds, ActiveX, SigGenRP, and BioSigRP.