I need to adapt a Bluetooth headset (speakers + mic) to 3.5 mm, but the only adapters I can find will either transmit or receive, not both at the same time. Is there some technical limitation why this can’t be done, or is there just no market for such a device? Thanks.
The technical limitation is bluetooth profiles. You can either have A2DP for good audio quality and single-direction, of HFP for terrible quality both ways. The target audience of these products doesn’t understand that it’s one or the other, so the devices just do A2DP and not HFP so the manufacturers don’t have to deal with angry stupid customers.