What is the Rx switch on my BT01 transciever?

Your BT-01 transceiver has three switches on it's front side. Tx, Off and Rx. To use your Audeara A-01's with your television, you should have the switch to Tx to transmit sound from your television to your headphones. 

Receive or Rx mode will transfer the sound in the opposite direction e.g. from your smart phone to an older stereo or speaker. Rx mode will not work with the Audeara A-01 headphones.