You’ll want to make sure that whichever side of the Wireless Y-Adaptor (A or B) that is plugged into the Leitner on Unibase mode is NOT on mute.
Feel free to mute the other side, though, if you’d like.
Please also note that you will not hear Unibase mode in the 2nd headset until you are on a call. The Wireless Y-Adaptor only works on telephone lines. So, no phone call, no Y-Adaptor link.
You can now connect 2 headsets, a phone, and a computer.
I’d like to thank Edward, Erin, Jo, and Bruno Mars for helping me with this experiment.