http://www.engineersgarage.com/microcontroller/8051projects/interface-serialport-RS232-AT89C51-circuit
In the above link, can anybody explain the following function:-
void recieve() //Function to receive serial data
{
unsigned char value;
while(RI==0);
SBUF=value;
P1=SBUF;
RI=0;
}
What will be the value of SBUF? 
Actually I want to say how come the project described in the above link suppose to run properly without getting a value in SBUF?