TTL Integration Guide

Synchronize your behavioral experiments with neural recording systems

What Is TTL & Why It Matters

TTL (transistor-transistor logic) pulses let ConductMaze mark the exact moment a behavioral event occurs in your electrophysiology, calcium imaging, or video recording. Two frame formats cover every paradigm.

Simple Protocol — 6-Byte Frames

Designed for maze navigation paradigms. Each frame timestamps an IR sensor trigger or trial boundary as a single pulse on one BNC channel. No event-type routing needed.

[0xAA] [0xBB] [event] [duration] [0xCC] [0xDD]

T-Maze arm entries and exits
Radial Maze arm visits
Y-Maze alternation events
Trial start / trial end markers

Complex Protocol — 9-Byte Frames

Built for conditioning and operant paradigms. Routes shock, tone, and light events to separate BNC channels so your recording system can distinguish event types without post-hoc parsing.

[0xAA] [0xBB] [chamber] [0x09] [duration] [voltage] [bnc_ch] [0xCC] [0xDD]

Fear Conditioning (shock + tone + context)
Operant Chamber (lever press + reward + cue)
Active Avoidance (CS + US routing)
Startle Response (prepulse + startle stimulus)

Signal Path Overview

From software event to neural recording timestamp, the TTL signal passes through four stages:

ConductMaze Software — Event trigger originates in the experiment control software
TTL Module — 16 channels, 3.3V/5V selectable, 10ms pulse increments. Serial connection at 115,200 baud, 8N1
BNC / DB-25 Output Connector — Single, 6-channel, or 25-pin output depending on your configuration
Recording System — Digital input receives the timestamped event marker

Configuration Notes

COM Port: Configure in ConductMaze Settings > TTL. Serial connection at 115,200 baud, 8N1.
Pulse Duration: Configurable in 10ms increments. Default: 10ms. Adjust for recording system requirements.
Voltage Levels: Jumper-selectable 3.3V or 5V logic. Match to your recording system's digital input spec.

Connector Types

Single BNC

1 channel, 3.3V or 5V. One output channel with jumper-selectable voltage. All events appear as pulses on a single line. Best for simple on/off signals and single-channel sync.

BNC-6

6 channels, 3.3V fixed. Six separate BNC outputs. Routes different event types (shock, tone, light, lever) to dedicated recording channels for real-time event discrimination. Best for conditioning paradigms.

DB-25

25 pins, parallel. Standard 25-pin parallel connector for high channel count systems. Commonly used with National Instruments DAQ devices that accept digital I/O via a DB-25 ribbon cable.

Compatible Recording Systems

ConductMaze TTL output works with all major electrophysiology and imaging platforms.

System	Connection	Notes
Open Ephys	BNC → digital input	Direct connection, 3.3V logic
TDT (Tucker-Davis)	BNC-6 → digital input	Multi-channel routing recommended
Neuralynx	BNC → TTL input port	5V required, check jumper setting
Inscopix nVista/nVue	BNC → trigger input	Frame-sync trigger mode
Noldus EthoVision	USB adapter → TTL bridge	Requires ConductMaze adapter
ANY-maze	USB adapter → TTL bridge	Requires ConductMaze adapter
Plexon	BNC → digital input	OmniPlex compatible
NI USB-6501	DB-25 / USB	24 digital I/O lines

Troubleshooting

Signal polarity mismatch

The TTL module has a jumper-selectable active-high or active-low output. Most recording systems expect active-high signals (a 0V to 3.3/5V transition marks an event). If your recording system shows no response to TTL pulses, flip the polarity jumper labeled POL next to the BNC output bank.

Ground loops

Ground loops occur when the TTL module and recording system have separate power supplies with different ground potentials, creating noise or false triggers. Fix: Connect the ground between systems via the BNC cable shield. If using the DB-25 connector, ensure pin 25 (ground) is connected to the recording system's ground reference.

Verifying signals before experiments

ConductMaze includes a Test Pulse button in Settings > TTL that sends a single pulse on each configured channel. For hardware verification, connect an oscilloscope or a simple LED test circuit (LED + 330 ohm resistor) to the BNC output. You should see a clean square wave at the configured voltage level.

50ms post-send delay between frames

ConductMaze firmware enforces a 50ms delay after transmitting each TTL frame to prevent serial buffer overflow. Back-to-back events closer than 50ms apart will be serialized. For most behavioral paradigms this is not a limitation. If sub-50ms event timing is critical, contact us about the high-speed TTL module option.

COM port not detected

Open Device Manager and expand "Ports (COM & LPT)" to verify the TTL module appears as a COM device. Try a different USB port. Replace the USB cable — charge-only cables lack data lines. Ensure the correct COM port number is selected in ConductMaze > Settings > TTL.

TTL Protocol Pages

Maze Navigation Protocols

T-Maze, Radial Maze, D-Maze, Y-Maze, Lickometer — 5 protocols for spatial navigation paradigms using 6-byte simple frames.

Conditioning & Operant Protocols

Fear Conditioning, Active Avoidance, Self-Administration, Operant Chamber, Startle Response — 7 protocols using 9-byte complex frames.

Third-Party Adapters

Noldus EthoVision, ANY-maze, Inscopix nVue, Plexon, NI USB-6501 — step-by-step setup instructions for each platform.

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