The connector box allows you to conveniently connect your instruments to the IOtech
Daqboard/2000 data acquisition card in your PC.
Connect the cable on the back of the box to the IOtech Daqboard/2000 data acquisition card.
Connect your instruments to the connectors on the front of the connector box.
The various connectors are:
- Eight BNC jacks labelled CH0, CH1, CH2, CH3, CH4, CH5, CH6, and CH7 that serve as recording channels.
- Two BNC jacks labelled AOUT0 and AOUT1. Use these to output ±10V 16-bit analog waveforms at a sampling rate of 50 kHz.
- One 3.5 mm stereo phone jack. Use this to output 50 kHz audio waveforms to computer speakers.
- Four BNC jacks labelled DOUT0, DOUT1, DOUT2, and DOUT3. Use these to output digital
TTL waveforms (trigger pulse patterns for stimulators) at a sampling rate of 50 kHz.
- Two BNC jacks labelled D0 and D1. Use these non-waveform-quality digital outputs to
switch TTL-triggered devices on and off during the course of an experiment.
We explain these connectors in more detail below.
Recording Channels CH0, CH1, ..., CH7
For most experiments, each recording electrode feeds into some signal conditioning
device such as an amplifier and/or a filter (esp. low cut and/or anti-alias).
The output of the signal conditioning device(s) for each recording electrode is
connected to one of the 8 input channels CH0, ..., CH7 of the NAC 2.0 connector box.
Although your original signal need not be a voltage (it could be a current, for example),
the output of your signal conditioning device must be a voltage within the
range ±10V (or less, depending on the gain you set on the DaqBoard/2000 data acquisition card).
data acquisition program assumes that the original signal that you are
measuring is directly proportional to the voltage it measures.
Digital Output Waveform Channels DOUT, DOUT1, DOUT2, and DOUT3
Most users have a stimulator that delivers the actual current or voltage pulse to a
stimulation electrode in the brain tissue.
When used with NAC 2.0, the stimulator is typically set up
to output one pulse to the stimulation
electrode each time the stimulator receives a TTL trigger pulse from NAC.
is set up to output digital waveforms that are patterns of trigger pulses
sent to the stimulator(s) from one or more of the digital waveform output
channels DOUT0, ..., DOUT3.
Note that because the NACGather
software can deliver just about any pattern of
trigger pulses, for most experiments, you may not need to purchase an expensive
stimulator to generate patterns of stimulations (e.g., bursts,
trains, etc.). You may be able to save money by purchasing a stimulator that simply
outputs a single stimulation pulse to your stimulation electrode for each trigger pulse
that the stimulator detects in the digital waveform from one the digital output waveform
channels DOUT0, DOUT2, ..., DOUT3. Use NACGather
to generate the stimulation patterns.
Analog Output Waveform Channels AOUT and AOUT1
In some cases, the user may have a stimulation device whose output is proportional
to a voltage waveform. In this case, the user may send analog waveforms from output
channels AOUT0 and /or AOUT1 to the stimulator.
The advantage of this is that the user can control stimulation amplitude, duration,
and waveform from within the
program instead of by manually adjusting stimulator controls.
The 3.5 mm stereo phone jack fits most computer speakers and headphones.
You can use this for experiments in which you want to stimulate an animal with sound
rather than an electrical impulse. NACGather can read in uncompressed WAV files
(a common sound file format), resample them to 50 kHz, and play them to (amplified)
speakers while data is recorded on the recording channels.
Note that the left and right sound channels are shared with analog waveform outputs
AOUT0 and AOUT1.
Non-Waveform Digital Output Channels D0 and D1
The NAC 2.0 connector box has two non-waveform digital outputs, D0 and D1 that output
TTL digital values (0V or 5V). These channels are meant to be used to turn devices
(e.g., pumps) on or off from within NACGather during the course of an experiment.
The user can set these channels to automatically change at the beginning or end of
stages of an experiment or the user can manually change these digital outputs
data acquisition program.
The types of changes that can be made on these channels are
- pulse high (0V→5V→0V),
- pulse low (5V→0V→5V),
- go high (0V→5V) and
- go low (5V→0V).