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  "title" : "Audio Input Routes"
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# Audio Input Routes

Strings that identify the various audio input sources for a device.

## Discussion

These strings are used as values for the [`kAudioSession_AudioRouteKey_Type`](/documentation/AudioToolbox/kAudioSession_AudioRouteKey_Type) key for the dictionary associated with the [`kAudioSession_AudioRouteKey_Inputs`](/documentation/AudioToolbox/kAudioSession_AudioRouteKey_Inputs) array.

## Topics

### Constants

[`let kAudioSessionInputRoute_LineIn: CFString!`](/documentation/AudioToolbox/kAudioSessionInputRoute_LineIn)

A line in input

[`let kAudioSessionInputRoute_BuiltInMic: CFString!`](/documentation/AudioToolbox/kAudioSessionInputRoute_BuiltInMic)

A built-in microphone input.

[`let kAudioSessionInputRoute_HeadsetMic: CFString!`](/documentation/AudioToolbox/kAudioSessionInputRoute_HeadsetMic)

A microphone that is part of a headset.

[`let kAudioSessionInputRoute_BluetoothHFP: CFString!`](/documentation/AudioToolbox/kAudioSessionInputRoute_BluetoothHFP)

A microphone that is part of a Bluetooth Hands-Free Profile (HFP) device.

[`let kAudioSessionInputRoute_USBAudio: CFString!`](/documentation/AudioToolbox/kAudioSessionInputRoute_USBAudio)

A Universal Serial Bus (USB) input, accessed through the device 30-pin connector.


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