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iCon Behavioral Control Interface

The iCon is a behavioral control interface designed to support easy or complex behavioral experiments. It has interchangeable analog and digital modules to fit the needs of any experimental paradigm. It can control most third-party behavioral chambers. The iCon connects directly to any TDT RZ processor with a DSP-M or optical quad DSP card and is controlled with TDT's Synapse software — resulting in high-bandwidth, precision control of behavioral hardware with real-time signal monitoring and full integration with neural recordings.

The iCon is available with two (iCon2) or four (iCon4) module slots. It is configurable with the following modules:

Physical Setup

The iCon connects to a DSP-M or optical QZDSP card in your RZ processor.

Single iCon connected to a DSPM card in an RZ5D

You can connect multiple iCons to the same DSP interface card.

Two iCons connected to a single DSPM card in an RZ5D



The iCon is powered by an integrated switched-mode power supply. The power supply auto-detects your region’s voltage setting and no further configuration is needed. The power switch is located on the back panel.

Status Light

The iCon front panel display Status light reports system connection information.

LED status Description
solid red no connection
solid green connection to DSP
blinking green connected and experiment is running in Synapse
blinking red Synapse is trying to access a module that doesn't exist, for example if your experiment is using a module that is not installed in the iCon

I/O Control

At the most basic the TDT iCon system can replace existing devices such as the Med Associates, Colburn or Lafayette systems that interface to a standard operant or behavioral box with input and output lines, where the output lines drive feeders, lick meters and other devices that require more than a digital trigger. At the more complex level the TDT system can be used to send and receive complex signals to control multiple hardware devices.

Replicating an Existing Behavioral Control System

The TDT system provides a unifying interface for sending and receiving behavioral information from a behavioral control box without the need for the external devices from these other companies.

iCon Control

The iCon can be controlled in the following ways:

  1. Bi-directional real-time communication between the iCon and an RZ processor, running in Synapse.

  2. Client software using the SynapseAPI to control the iCon outputs through Synapse.

  3. Pynapse Python Coding Gizmo in Synapse controlling the iCon outputs and managing full behavioral state control.

The iCon object in Synapse lets you configure how the iCon modules are controlled (either through real-time signals on the RZ itself, client-controlled via the SynapseAPI, or directly integrated in a Pynapse gizmo) and how to route iCon input state changes for storage or further closed-loop processing.


iH10 High Voltage Interface

The iH10 features 10 bidirectional interface ports to provide direct control of high-voltage (e.g. 28 V signal) cage elements including Med Associates and Lafayette.

  • The ports are configurable in Synapse as either inputs or outputs
  • Manual trigger buttons simplify testing and debugging of connected behavioral components
  • Status lights make it easy to monitor component activity during sessions

The 'O' LED lights when the port is driven by Synapse, and the 'I' LED lights when the port is driven by Synapse, by an external device, or by the manual button press.

The iH10 uses 1.57 mm diameter standard Molex pin and socket connectors. An output port can source up to 1 A maximum. The maximum total output per iH10 is 1 A. The maximum total output per iCon is 3 A.

For information on software control of the iH10, see the Synapse Manual.

iH10 Pinout

Pin Name Description
G Ground
S Signal Input or output signal
V+ +28 V +28 V up to 1 A, 3 A max per iCon

As an Input, the Signal line floats to +28 V. Short the Signal line to ground to trigger it. As an Output, the Signal line floats by default and is shorted to 0 V when triggered.

iM10 Multi-Function Interface

The iM10 has multiple specialized I/O functions, including advanced audio processing for auditory behavioral experiments.

  • Drive a speaker (e.g. MF1) directly up to 4 W via an RCA connection.
  • Record cage sounds via an embedded microphone amplifier.
  • Connect with many common cage elements (e.g. touch sensors) via BNC ADC inputs and DAC outputs.
  • Streamline setup with a range of embedded signal processing options.

The iM10 analog input / output range is ±5 V. The onboard analog processing runs at 800 kHz, independent of the RZ sampling rate.

For information on software control of the iM10 and all of its available features, see the Synapse Manual.


The iM10 has four analog inputs. Inputs 1 and 2 have a 50 kOhm input impedance and feature an optional microphone amplifier with 40 dB, 50 dB, or 60 dB gain and attack/release ratios of 1:500, 1:2000, 1:4000. When using the microphone amp input, note that the input signals are inverted.


Do not connect anything to the BNC Inputs 1 and 2 when the microphone amp is enabled.

Inputs 3 and 4 have a 10 kOhm input impedance by default with optional adjustable input impedance and bias voltage. Options are:

  • 10 kOhm to Ground
  • 1 kOhm (+5 V positive bias)
  • 50 kOhm (+5 V positive bias)
  • infinite input impedance

The inverting input (BNC shell) can either be tied to Ground or a -5 V negative bias.

Add up to 60 dB gain to the signal on each individual input.

Each Input has two LEDs. The top LED is a clip light that flashes if the input signal is >~4.75 V. The bottom LED is a signal LED that will light when that processed input triggers.

Touch Inputs

The iM10 has two touch sensor inputs. These have an independent ground. They use a 750 nA current and trigger if the measured impedance between the input and ground is <=10 MOhm.


The iM10 has four analog outputs. The outputs have a 10 Ohm output impedance. Output a pre-programmed set of waveforms (DC Voltage, Tone, White Noise, Pink Noise, Square, Clock, or PWM), or a user-defined waveform. See the Synapse Manual for the full list of options.

Outputs 1 and 2 are paired. This means the choice of waveform shape for Output 2 can be limited depending on the selected waveform for Output 1. Also, the signals generated by Output 1 and Output 2 can be mixed to play out a single speaker.

Likewise, Outputs 3 and 4 are also paired.

The iM10-generated waveforms use a ±5 V amplitude. Apply up to 50 dB attenuation to each individual output, adjustable at run-time.

Each Output has two LEDs. The top LED is a clip light that flashes if the output signal is >=4.9 V. The bottom LED is a signal LED that will light when that output is enabled.

The RCA connectors can directly drive speakers. These connectors are driven differentially to give more power out. The RCA connectors should only be connected to speakers. If you are controlling an external amplifier then use the BNC outputs.

iL24 Digital Logic Interface

The iL24 module can communicate with external behavioral components using 24 bits of 5 V or 3.3 V TTL logic signals.

  • There are four bit-wise inputs and four bit-wise outputs available with BNC connectors and status light for each
  • The DB25 connector has access to all 24 addressable bits
  • Two rows of 8 status LEDs on the front panel show the state of the word input and output bits
  • The front panel switch toggles between +3.3 V and +5 V logic for all 24 bits of I/O on the iL24
  • Each bit can source up to 6 mA maximum current

For information on software control of the iL24, see the Synapse Manual.

DB25 Pinout

iL24 pinout, looking into the connector

Pin Name Description Pin Name Description
1 BO1 BNC Output 14 BO2 BNC Output
2 BO3 15 BO4
3 BI1 BNC Input 16 BI2 BNC Input
4 BI3 17 BI4
5 GND Ground 18 DO0 Word Output
6 DO1 Word Output 19 DO2
7 DO3 20 DO4
8 DO5 21 DO6
9 DO7 22 DI0 Word Input
10 DI1 Word Input 23 DI2
11 DI3 24 DI4
12 DI5 25 DI6
13 DI7

iR5 IR Driver Interface

The iR5 is a specialized interface for up to five infrared sensor beams. This module has built-in power and logical connections to drive external IR sensors and sends TTL events whenever the subject crosses the beam, without the need for any external signal processing.

  • Manual trigger buttons for each IR port simplify testing and debugging
  • Status lights for each IR beam monitor subject movement during sessions.

For information on software control of the iR5, see the Synapse Manual.

Output Power

The IR LED output power is adjustable through Synapse software configuration (1-8). This adjusts an in-line resistor value from 4 kOhm to 500 Ohm. Power output depends on this power setting and the voltage drop of the LED. The table below shows the supply current for a typical IR LED with a 1.4 V voltage drop.

Setting Supply Current (mA)
1 0.9
2 2.7
3 4.5
4 6.3
5 8.1
6 9.9
7 11.7
8 13.5

Sensor Input

The sensor power output has a 10 ohm resistor in line. The output voltage changes with the current draw as follows:

Current Draw (mA) Voltage
1 3.29
3 3.27
10 3.2
30 3
100 2.3
300 0.3

iR5 Pinout

Pin Name Description
V+ Sensor power +3.3 V with 10 Ohm in-line resistor
G Ground
S Sensor Sensor output

When the Sensor output is pulled low, it triggers the event.

Pin Name Description
V+ Driver voltage +5 V output with a variable in-line resistor
T Toggle line Determines if power output is on