Code:

//Declaration:
xdata unsigned int data1=1;
xdata unsigned int data2=1550;
xdata unsigned int data3=15550;

//Configure UART

void serial_init(void)
{
T3CON = 0x83; //configure timer 3...
T3FD = 0x12; //...for 9600 baud
SCON = 0x50;
TI=1; //Initialise to send
}

//Output to UART:
printf("DATA 1:%un",data1); //Output result to UART
printf("DATA 2:%un",data2); //Output result to UART
printf("DATA 3:%un",data3); //Output result to UART

//Note: the end of line command "%un" on above codes does not appear correctly when I post the message.

Output on HyperTerminal:

DATA 1:53925
DATA 2:53926
DATA 3:30127
;--------------------------------------
Very strange result if I use "unsigned int" data instead of constant.