title: Bluetooth low energy specification Heart rate profile vs heart rate service
body: <p>I am trying to understand how Bluetooth BLE works on the iOS programming side. On page <a href="https://www.bluetooth.org/Technical/Specifications/adopted.htm" rel="nofollow">https://www.bluetooth.org/Technical/Specifications/adopted.htm</a>, there are two specifications, heart rate profile and heart rate service.</p>
  
  <p>On the introduction of Heart Rate Profile it says </p>
  
  <blockquote>
    <p>The Heart Rate Profile is used to enable a data collection device to
    obtain data from a Heart Rate Sensor that exposes the Heart Rate
    Service</p>
  </blockquote>
  
  <p>On some service like the battery level there is no corresponding profile. What's the difference between the two? One for the sender (service) and one for the receiver (profile)?</p>