> For the complete documentation index, see [llms.txt](https://emotiv.gitbook.io/extender-manual/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://emotiv.gitbook.io/extender-manual/hardware_triggering/trigger-cable.md).

# Trigger Input & Cable

The Extender trigger input requires a 2.5mm audio connector which has an outer diameter of less than 6.8mm to fit into the socket.

![](/files/-LIeS1UyUNVFmET3Rz83)

EMOTIV has provided a 1m trigger cable with every Extender. It features the required low profile connector on one end and has two tinned wires (red and black) for connecting to your trigger source. We have provided some examples of an arduino scripts. 

Example 1: generates 100 pulses at 1s intervals.

Example 2:  Sends a trigger pulse each time the trigger character is recieved on the arduino serial port.


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