Distinguish Serial Data?

[6600gt]

How can you distinguish a group of bytes(data) form another?
Other than using a unique byte in front a group of bytes.

I just can't figure out how to do it.

For example, I am writing a program that sends a group of bytes periodically. I need to write a program that can distinguish between this data and data that I would type into the terminal window(not periodical). These are different programs so there is no way to syncronize them.

Now I know that only one program can access the serial port at any given time. The program I am writing allows you to turn the serial port on and off. This allows the terminal window to access the serial port without exiting my program.(Might need to restart the IFI loader again)

The only thing I could think of was to send a unique byte in front of the group of byte that I am about to send to the RC, so it can distinguish it from another group. What if I coincidentally typed that same unique starter byte in to the termial port-> ? What do I do now?

Thanks.