Let's suppose that you have bought and are using the Wake Up Service with 5 simultaneous lines. That means that our service is able to accept 5 concurrent customer lines, so the 6th customer who's going to use the service will get a busy tone. The service will not be able to use more than 5 lines.
Let's suppose that we are using the Wake Up Service with 5 simultaneous lines again and 20 of our customers set their alarm time to 07:00 the morning. At the first second after 07:00 the Service is going to open 5 concurrent lines and make a wake up call to each of the customers who have activated the service. When a customer answers the alarm call, the wake up message (Wav file) begins to play. After the Wav file is done playing, the service hangs up and sets the line free (the line also gets free in the case that the customer hangs up before the message is finished).
As explained above, in this case lines are unavailable for 2 to 60 seconds (depending on the customer reaction).
The next 15 customers who are enqueued are going to receive their alarm call when the Wake up easy Service finds an available line. Every action or request to the service is going to use the availiable lines.