The BA3121 is an audio (ground loop) isolation amplifier. In the datasheet there is no simple pinout picture with names of the pins, so I draw this pinout picture by following the block and the circuit operation diagrams. It takes me some time to do this (i am not an expert).
Before I try/continue, I want to be sure my findings are correct. Is this okay?
I have also some doubts about the pin order because mostly, the 5th pin is the upper-right pin. What is Vm1 and Vm2 in the schematics, what is "Vm" and why is it called "Vm"?
The pictures I have used to come to this:
You can find the full datasheet here: