How to access EAAccessories?

eaManager = [EAAccessoryManager sharedAccessoryManager];
开发者_Go百科[eaManager registerForLocalNotifications];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(gotDevice)  name:EAAccessoryDidConnectNotification object:nil];

[eaManager connectedDevices] is always empty.

How can I pair to a accessory?

You need to connect your iPhone to a Made for iPod program device which provides a protocol for being accessed by the External Accessory framework. There aren't many of those out there right now. I believe that TomTom's iPhone Car Kit is one of them, but I can't think of others.