problem with serial communication

hi,

i use the function SER.readbyte() on the GM862-quad:

i send by serial port some bytes with PC

a=SER.readbyte()

and a=0

but a=0 what does it means?

because with an another program the function SER.readbyte() return the value send by the serial port

so i don’t understand because its nearly the same program

So if somebody have an idea…

thanks