[GreenKeys] What is the RTTY standard for CR LF for transmission?

[Mike Willegal]

I’m working on improving a vintage computer (Apple II) app for RTTY.

There are a number of possibilities and I wondering if there is a convention for CR/LF usage.

Is it expected that there is a CR/LF at the end of each message?
Are there cases where CR/LF are sent before messages?
Which goes out first, the CR or LF?

Thanks,
Mike Willegal