RX—–aptX Adaptive/aptX HD/aptX/AAC/SBC. TX—–aptX Adaptive/aptX HD/aptX LL/aptX/SBC. Bluetooth Profile: aptX Adaptive/aptX HD/aptX LL/aptX/AAC/SBC. —The function of the bluetooth transmitter is to add a bluetooth function to devices without bluetooth function such as TV/computer, so that they can connect to bluetooth speakers/headphones.