Let us imagine a bidirectional buffer for which You and I serve as the input and output..
C'mon,it's neither a voltage nor current buffer..but the one which keeps track of the vexatious signals being transmitted..
The status flag indicates which of the two users are active..let's say me now..
The directional flag when set transmits the signal from left to right,i.e from me to you..
The receive_rdy flag(active high) indicates if the other user aka you are ready to receive..
Now that the ambiance is all set for a successful transmission,i start irritating you..
The receive buffer in the receptive side indicates if you are totally god-damned or you have the fortitude and stoicism to bear more..
Once your receive buffer is full,the signals do not get transmitted any more..
The reverse happens too when all the flags are in the vice-verse condition..
From the description it has to be obviously clear that there's no full-duplex transmission..Only either of us dominate the irking..
PS:Humans with XY have the knack to irritate others.. and the ones with XX have whining dominating their repertoire..So there's less of signal transmission when the users in question are of the same gender..