i want to send hexadeximal values through uart port
from one microntroller to another the problem is when i give decimal or hexa decimal values to send it is displaying unknown values in terminal i am using keil3
for programming and microntroller is 89s52 atmel
here is the code
org 0000h
mov ie,#00h
mov sp,#08h
mov tmod,#20h
mov scon,#50h
mov th1,#-3
setb tr1
up:
mov a,#30h
acall serial
sjmp up
serial:

mov sbuf,a
jnb ti,$
clr ti
ret
end
if i give double codes it is displaying for example
mov a,#"a"
please give me the solution
using max 232 communication