You titled the Thread, "Parallel Async Communication Protocol" - so yes, you did say that the Protocol is Async.

Actually, your problem is that you are confusing the the Protocol with the hardware implementation of the interface.

In fact, as I said originally,your Protocol does not require any specific hardware implementation: you could use serial or parallel; you could use synchronous or asynchronous; you might or might not include FIFOs;...

As I said earlier, In protocol-speak, the hardware implementation is Layer-1, and this protocol is Layer-2, and the two can be treated independently.