Sorry for the confusion, Eric & Andy. I thought I have to use buffer when send and receive to avoid data being missed. And as I have seen in INTSIO example project:

#define TBUF_SIZE	256		/* DO NOT CHANGE */
#define RBUF_SIZE	256		/* DO NOT CHANGE */

static xdata unsigned char tbuf [TBUF_SIZE];
static xdata unsigned char rbuf [RBUF_SIZE];

static xdata unsigned char t_in = 0;
static xdata unsigned char t_out = 0;
static xdata unsigned char t_disabled = 0;

static xdata unsigned char r_in = 0;
static xdata unsigned char r_out = 0;

 

I have to do similar like that. I am OK with sending/receiving a single character. My problem is how to read a string from PC and return with result without data being lost. To be honest, I am new to this so often get confuse which method to implement...

Thanks,
Ralf