BT.
if your tascam is old i suspect its not multi client.
I’m not sure exactly what you mean by “multi-client”. The website or user manual doesn’t seem to specifically mention “multi-client”.
Normally ASIO drivers only support one audio interface at a time. Multi client is a special wrapper that allows another device to access it. You can do a search for Multi client ASIO driver and it will give you the technical information about how this works. I don't think I am giving you the exact details of how this works.