I have a covert recording of what happened to those US diplomats.
The audio signal is at 1:15
https://www.youtube.com/watch?v=4wwQpACwcoM
We can see typical Cuban technology apparently dating from the 1960's.
ETA
A paper reviewing the issue here.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5528197/