what's the difference between LFLine Fee and NL New line 4449

I found a document breastled "Some Notes on Teletype Corporation", which it seems is written by "someone" who worked (?) there, and may have been directly involved:

I remember newline being talked about, but not much of what was said about it. The basic idea was to make the TTY machine more typewriter-like; and typewriters have a single key for carriage return and line feed. It takes some extra learning for a typewriter typist to use a Teletype machine.

One might wonder why the LF character was chosen as NL rather than the CR character. I believe the reason was compatibility. If you send CR-LF to a machine that is set up for NL, then the carriage returns and the line spaces once, which is what you had in mind. Whereas if CR had been used for the newline character then sending CR-LF would result in two line spaces rather than one.

This fellow seem to know what he's on about! ;-)

I got a particular kick out of this sentence,

It takes some extra learning for a typewriter typist to use a Teletype machine.

Going from a Teletype machine to a computer keyboard was an interesting learning experience too...

--