The ActiveTwo USB receiver has 16 independent trigger inputs and 16 independent trigger outputs (TTL level, 37-pole sub-d connector on the front panel of the receiver).
The inputs all have a 'Pull-up' resistor of 10 Kohm to 3.3 Volt. So if the trigger inputs are left unconnected they will be high.
The input triggers are mixed with the digital data coming from the AD-box. The input triggers are saved in an extra channel (the status channel), with the same sample rate as the electrode channels. So, the timing of the trigger inputs is accurate to the time period of a sample.
The trigger outputs can be controlled by software. ActiView Light (developer software) has a LabVIEW routine integrated which is able to control the trigger outputs.
Because the trigger inputs are located at the receiver, the trigger inputs and connected trigger equipment remains completely galvanically isolated from the front-end and the subject, this ensures that the trigger equipment can not cause any additional interference and provides optimal subject safety.
Because our acquisition software saves the electrode signals and trigger signals in .BDF (BioSemi Data Format), off-line ERP analysis can be performed with one of the many available third-party software package that are compatible with the .BDF format. Manufacturers who support the .BDF format automatically read our digital trigger format. No old fashioned setting of analog trigger levels etc is needed.
ActiView always automatically saves all 16 Triggers in an extra channel. It is not possible to NOT save the triggers. (to prevent any user mistake)
In ActiView, the incomming 16 trigger lines can be displayed on several ways.
At the configuration tab-page you can select for example to display the triggers on an Analog way or on a Decimal way.
When the 16 trigger input lines are display on an Analog way, each of the individual 16 trigger inputs will be displayed as a separate bit.
You can use the "Analog" mode to inspect unexpected trigger behavior.
In "Digital" display mode, the triggers will be displayed as 2 groups on 8-bit numbers (lines 1-8 and lines 9-16), each trigger group will have a value between 0 and 255.
In the tables below you can find the connections of the trigger input and a description of the Status channel.