Bypass mode means a direct cable connection. It connects your TV and your external wired soundbar or speakers directly.
It works under TX mode & OFF mode.
In OFF mode, only Bypass works. Then you can hear the TV sound from your soundbar.
In TX mode, Bluetooth function and direct cable connection work simultaneously.Then you can hear your TV sound from both your soundbar and bluetooth headphones.
Bypass can only work with the same type of input/output. AUX input to AUX output or OPT input to OPT output.
Here are two typical scenarios to use bypass features.
1. Your TV has only one optical output, it is connected your soundbar already, but you want to watch TV with headphones wireless for night shows, then you don't want to plug/unplug any wire frequently.
2. For those family who want to watch TV together, but someone is hearing impaired who wants to use BT headphone with high volume and other members want to normal volume. But their TV don't supports internal speaker and Bluetooth output simultaneously. Then you can use Oasis Plus to achieve this function. One can hear sound from AS9S headphones, others can hear sound from your external soundbar or speakers.