[RTTY] hyphen or no hyphen

[Don Hill AA5AU]

In my experienced opinion, Kok Chen is the foremost expert in the technical knowledge of RTTY that I know.  I think we all benefit
from his expertise.  I know I do.  After over 20 years of RTTY operation, I still get confused over what is written and what I see
on my screen (thousands of times).

Chen, can you please confirm what USOS (Unshift on Space) is exactly and how it's done.  It is my understanding that USOS returns
the decoder to LETTERS after a space.  If this is the case, then how can it be explained that I see a lot of "AA5AU TOO 001 001"
reports where the signal report ends up in LETTERS but the actual serial number ends up in FIGURES?  How can this be explained if a
LETTERS shift is sent after the space between "TOO" and "001" or was the sending station not using USOS?  I see it too often.

Now, here is where I really get confused.  I've read that USOS has to be enabled on both the transmit and receive end.  It's fairly
simple to understand that the transmit end sends a LETTERS shift after a space character, but why and how is USOS set up on the
receiving end?  

I think we all can agree that sending hyphens between LETTERS groups and FIGURES groups is a bad thing, such as "AA5AU 599-LA-LA".
But it would seem that sending "AA5AU 599-001-001" could actually be faster (less characters?) than "AA5AU 599 001 001".  Is this
true?  I feel there is a reason for using spaces instead of hyphens even between FIGURES groups.

If you have a need to shorten your exchange by a few milliseconds, can using hyphens instead of spaces between FIGURES groups be
time effective?

Can we bank on everyone using USOS these days?

One more thing.  My RTTY days actually go way back.  When I was a communications technician on the DEW line (and NARS -North
Atlantic Radio System) in Iceland in the late 70's, I used to send tape all the time using a mechanical TTY machine.  I don't
remember which model.  I recall receiving bulletins and when we'd take a hit, the text would jump to the next line or return and
type over the existing line.  This NEVER happens in amateur RTTY.  Why?

Final question.  In today's ham RTTY programs, when you hit the ENTER key, do you send both a CR and LF characters (2 characters?).
I'm thinking yes.

Please, oh RTTY Master, enlighten us with your vast knowledge!!!

Thanks,
Don AA5AU



-----Original Message-----
From: rtty-bounces at contesting.com [mailto:rtty-bounces at contesting.com] On Behalf Of Kok Chen
Sent: Tuesday, February 13, 2007 2:38 PM
To: RTTY Reflector
Subject: Re: [RTTY] hyphen or no hyphen

Scott Nichols wrote:
> START OF MACRO...I prefer CR or ENTER (one line advance) to start the 
> macro on a fresh line, not CRLF, which advances it 2 lines...Anything 
> more than 1 line is not needed

If some software implements Baudot CR/LF as two newlines, then that bug should be fixed.

The Baudot CR (carriage return - octal 10) should simply return the type carriage to the beginning of the current line.  It should
not cause a newline to occur.  If you send CR without a LF to someone who is decoding with a TU into a mechanical teletypewriter,
you will be overprinting the line that you had previously transmitted to him.

LF (line feed - octal 02) is the Baudot code that rotates the teletypewriter platen to the next line.

Strictly speaking, a LF without a CR moves the type head to the current horizontal location of the next line, but you seldom see
that property implemented in "glass teletypes."

CR/LF has always been the convention used to move to the beginning of the next line.

The reason CR/LF is the convention for a newline and not LF/CR is to allow the mechanical carriage an extra 1/6 of a second to
settle when it is suddenly jerked from printing on the right side to printing on the left side.

When I was using the Model 33 (7 level teletypewriter in the computer
world) back in the 60s, I used to put out CR/CR/LF when I needed a newline since the Model 33 would often print an unstable first
character otherwise.  That extra CR causes no extra movement and serves only to delay the stream.

73
Chen, W7AY

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