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# channelManager(_:channelUUID:didBeginTransmittingFrom:)

Tells the observer that transmission began.

```
func channelManager(_ channelManager: PTChannelManager, channelUUID: UUID, didBeginTransmittingFrom source: PTChannelTransmitRequestSource)
```

## Parameters

`channelManager`

The channel manager.

`channelUUID`

The channel identifier.

`source`

The transmission request source.

## Discussion

The system calls this method when the user begins pressing the talk button in the user interface, a programmatic transmit starts, or transmission begins from a hands-free accessory button press.

> Important:
> Your app must wait for the system to call ``doc://com.apple.pushtotalk/documentation/PushToTalk/PTChannelManagerDelegate/channelManager(_:didActivate:)`` before you begin recording audio from the user.

---

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