On a Mac: USB Link switches the Bose 700 headphones to "call mode", resulting in poor audio fidelity
I have just received my USB Link and just as the post says, when the dongle is plugged in and I have an app playing music, the headphones switch to "call mode" within a few seconds.
This has four effects:
1) opens the microphone to the computer;
2) drops the audio fidelity to 16kHz Mono;
3) Passes microphone audio into the headset;
4) Lowers battery life signficantly.
#3 is a comfort thing designed to help people hear themselves talk.
It's behaving as if the microphone is being used as an active input, when in fact it is not. I've checked all apps that might have telephony (Teams, Jabber, Skype, Slack) and they're all cleared. The MacOS audio input is 'Internal microphone' but it makes no difference if I switch to the USB Link or vice-versa.
I've used other UC systems like the Plantronics BT600 with UC 8200 headset, and also used these Bose 700's in Bluetooth mode. When there is no active call or that headset / dongle's microphone is not active, the system switches back to stereo ultra-wideband (44kHz).