# Train-Time Key Sets and Run-Time Key Sets

An OCVMax tool supports a train-time key set as well as a run-time key set. Use a train-time key set to specify all the character keys possible at a certain position, and a run-time key set to specify the expected character key at that position in the next run-time image. For example, a vision application might verify a string of numbers where the values at one or more positions within the string increase incrementally. As you configure an OCVMax tool, you would specify a train-time key set with all the numerical character keys, 0 - 9, at those positions. As the application operates, you would use a run-time key set of the next character key you expect based on the last image analyzed by the OCVMax tool. Using the run-time key set generally improves the performance speed of the tool versus having the tool compare the current character with every character in the train-time key set.