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.