try this test program. It will solve your problem.

#include<reg51.h>
//void Initialise();

unsigned char a[15] = {"The number is 1"};
unsigned char b[20] = {"The number is not 1"};
void main()
{
unsigned char i;

//Initialize(); //this function is Initialize LED

TMOD = 0X20;
SCON = 0x50;
TH1 = 0xFD;
TR1 = 1;

while(1)
{
while(RI==0); // While control is here type any number in
// serial window in debugging procces or
// hyperterminal
{
i=SBUF; // here i=0x31(which is hex and ascii of 1) and
//SBUF=0x00 and RI become 1
RI=0; //RI is cleared
SBUF=i; //SBUF and i both showing 0x31
if(i==0x31) //you can see this condition must true
//because(i==0x31)
{
for (i=0;i<15;i++)
{
while(!TI);
SBUF = a[i];
TI=0;
}
}
else
{
for (i=0;i<20;i++)
{
while(!TI);
SBUF = b[i];
TI=0;
}
}
}

}
}