Which concept generally preceded the specific form factor of integrated brake/shifter levers?
Answer
The function of indexing
The text indicates that the functional principle of indexing—the defined cable stops—existed in separate shifters (like downtube or bar-mounted) before manufacturers packaged that indexing mechanism with the brake lever into integrated units like STI.

Related Questions
What determined the position of the derailleur in friction shifting systems?What is the defining feature of modern drivetrains that moved past earlier friction adjustments?How did indexed shifting solve the problem of inconsistent cable tension?Which Shimano system is often credited with popularizing reliable indexed shifting by matching all drivetrain parts?What significant innovation combined braking and shifting functions into a single unit mounted on the brake hood?What was the primary mechanical weakness of early derailleur designs before reliable indexing arrived?Which concept generally preceded the specific form factor of integrated brake/shifter levers?According to the comparison table, what characterized the rider feel of friction shifting?What mechanical realization is identified as the core technological leap defining modern cycling performance over friction control?What type of development showed that the idea of indexing was not centralized in one corporate R&D department?