How do I bridge USB with mobile/analogue?
Since version 1.31 the way Konftel 300 handles USB connection has been changed. Due to this the way to make bridged calls with USB has changed as well.

When you have an active analogue/mobile call on the Konftel 300 just press the LINE MODE-button
and select USB to bridge the USB call.

When you have an active USB call and want to add analogue/mobile to the call. Press the green off-hook button, then press the LINE MODE-button and select USB (which was put on hold when you activated the analogue/mobile connection) to bridge the two connections.