Which code is used when no action is taken in response to a call?

The correct choice associated with indicating that no action is taken in response to a call is indeed Code 24. This code serves as a clear indicator for dispatchers and responders that a situation has been evaluated but does not warrant further action, perhaps due to it being a non-emergency or otherwise resolved issue.

Using Code 24 helps to maintain clarity in communications among emergency services personnel by categorizing call responses efficiently. Codes like Code 22, Code 19, and Code 20 serve different specific purposes within the dispatch framework, but they do not denote the same concept of having taken no action. Understanding these codes is crucial for effective communication and proper response handling in emergency dispatch operations.