Bell pushes (communication device)
Must be within reach of every priority seat
Adjacent to no less than every third row of seats
No higher than 1200mm from floor for seated passengers
No higher than 1500mm from floor for standing passengers
Contrasting colour
When pressed, activate an audible and visual device (on each deck in case of double decks) that is visible to the majority of passengers
I assume the bells on the Streetlites meet these criteria.