title: iOS bluetooth scanForPeripheralsWithServices no results
body: <p>When I use iOS bluetooth, code like this:</p>
  
  <pre><code>static NSString * const kServiceUUID = @"1802";
  [self.manager scanForPeripheralsWithServices:@[ [CBUUID UUIDWithString:kServiceUUID] ] options:@{CBCentralManagerScanOptionAllowDuplicatesKey : @NO }];
  </code></pre>
  
  <p>why no response? I have tried kinds of parameter pairs in method 
      scanForPeripheralsWithServices
  I have checked this question:
  <a href="https://stackoverflow.com/questions/10178293/how-to-get-list-of-available-bluetooth-devices">How to get list of available Bluetooth devices?</a></p>
  
  <p>My device is iPod touch 5 (jailbroken) with iOS 6. I have already test some bluetooth 4.0 devices. Can anyone tell me why?</p>