StimTracker can monitor up to six digital (TTL) input lines and generate event markers based on changes in these input lines. For convenience, the TTL Input connector was designed so that a simple and commonly available RJ45/Ethernet cable can be used between the Accessory Connector on Cedrus’ RB Series response pads and StimTracker:

This setup only works with the RB-x30 generation response pads. It will not work with the newer RB-x40 models.

The RB-x30 is typically connected to a computer via USB for two reasons: to obtain power, and to transmit the participant’s key press information. However, StimTracker provides power to the response pad via the Accessory Connector, making it unnecessary to use a USB cable if you don’t need to have the stimulus presentation software record key press information.

Note: when connecting an RB-x30 response pad to StimTracker, the Accessory Connector’s default “logic” is “active low”. In other words, the output of the pins is normally high, and goes to low when the participant presses a key. This default behavior can be changed to “active high” using an older version of the Xidon utility program (pronounced “Zydon”).

RB Series models earlier than the RB-x30 used a serial port instead of USB. Both generations, the RB-x20 and RB-x30, share a pin-compatible Accessory Connector. You can connect the earlier RB-x20 models to StimTracker as shown in the diagram above, with or without connecting the response pad to the computer’s serial port.

The TTL Input connector on StimTracker will work with any TTL compatible signal. It’s a matter of building the right cable. See Interfacing With StimTracker’s TTL Input Connector.