In the case where Control is sending data to Swipe, in conjunction with a keypad challenge, we
have the following steps:
- Control sends to Swipe.
- Swipe replies with, “OK, event primed.”
- A big delay occurs until the next person swipes their card.
- Swipe uses a pulse to say, “I have data available.”
- Control sends a message, “What is your data?”
- Swipe replies with, “Swipe card ID # xxxx was swiped.”
- Control sends message, “Challenge the user with YYYY.”
- Swipe replies with, “OK, challenge in progress.”
- A delay occurs while the user types in the response.
- Swipe sends a pulse to Control with, “Challenge complete.”
(We're assuming that the challenge response doesn't fit in a pulse.)
- Control sends a message, “What is the challenge response?”
- Swipe replies with, “Challenge response is IZZY.”
- Control sends a message, “change LED to GREEN.”
- Swipe replies with, “OK.”
- A 20-second delay occurs, while the door is opened.
- Control sends a message, “Change LED to RED.”
- Swipe replies with, “OK.”
In this case, there were two pulses and six messages.
Again, the initial priming message could be discounted.