====== TTL BNC ======
A "fiber to copper" box translate and enhances the pulse event from the scanner received over fiber optic cable to a longer and stronger signal to the button box, which is then presented to a task computer as a key press from the USB source (likely ''='' but previously ''^''). 
This simulated keypress is used to start an [[:mr:task|fMRI task]]. See [[:mr:task:trigger|Triggering Task Start]].

===== Errors =====

Some time in 2023-07 /* 2023-07-00 */ ⚠️ not all pulses were correctly converted to keyboard pushes on [[:scan:p2]]. As a result, a MR acquisition could have started before the task. 

In 2024-12 /* 2024-12-00 */, ✅ the TTL pulse hardware issue was resolved. The QC protocol includes confirming the "EPrime" computer receives all expected TTL-to-''='' pushes during the phantom EPI.

See https://github.com/NPACore/p2-timing-debug