In article ,
(David Griffith) wrote:

Does anyone here done something like sending ASCII to a microcontroller
which then emits morse code? I'm tinkering around with old telegraph
sounders.

David-

I understand the old telegraph sounders made a clack-clack sound rather
than a beep. They also used an earlier version of code than
international Morse, where some characters had mini-spaces in addition
to dots and dashes.

Either way, the solution may be similar. Use the ASCII code as an
address for locating the timing required for each character, stored in a
look-up table.

Use a basic timing subroutine. Call it once for a dot or a space. Call
it three times for a dash. Before calling it, turn on the output keyer
for Mark and off for Space.

If you didn't have an existing sounder, you could generate another
timing interval that would repeat at an audio rate for the amount of
time the Mark signal would be on.

Fred
K4DII

Fred McKenzie wrote:
In article ,
(David Griffith) wrote:

Does anyone here done something like sending ASCII to a microcontroller
which then emits morse code? I'm tinkering around with old telegraph
sounders.

David-

I understand the old telegraph sounders made a clack-clack sound rather
than a beep. They also used an earlier version of code than
international Morse, where some characters had mini-spaces in addition
to dots and dashes.

Either way, the solution may be similar. Use the ASCII code as an
address for locating the timing required for each character, stored in a
look-up table.

Use a basic timing subroutine. Call it once for a dot or a space. Call
it three times for a dash. Before calling it, turn on the output keyer
for Mark and off for Space.

If you didn't have an existing sounder, you could generate another
timing interval that would repeat at an audio rate for the amount of
time the Mark signal would be on.

I have a couple vintage sounders. Hook a batter and key in serial with
a sounder. When the key is down, the sounder clicks down. Let go and
it clacks up. So, a dot is "click-clack" and a dash is
"click-wait-clack". I think the Mark and Space stuff has to do with the
fact that the line was always kept energized, thus, an idle line would
hold the sounder arm down. That way you'd know immediately if there was
a line fault. That would be a bit wasteful now, so I suppose I should
preceed each message with a very long dash to at least try to fake that
part.


--
David Griffith
--- Put my last name where it belongs

David Griffith wrote:
\
I have a couple vintage sounders. Hook a batter and key in serial with
a sounder. When the key is down, the sounder clicks down. Let go and
it clacks up. So, a dot is "click-clack" and a dash is
"click-wait-clack". I think the Mark and Space stuff has to do with the
fact that the line was always kept energized, thus, an idle line would
hold the sounder arm down. That way you'd know immediately if there was
a line fault. That would be a bit wasteful now, so I suppose I should
preceed each message with a very long dash to at least try to fake that
part.



As I recall there is international Morse Code and American Morese code..
Two different codes, and one (American I think) is better suited to the
click/clackers and guess what.. That font of much knowledge

http://en.wikipedia.org/wiki/American_Morse_code

Has an article on it at the above link INCLUDING the code itself!!!!

Also called the Railroad code.. IT is not as suited to radio as
International Morse code is.

As to the line running energized.. There are several reasons for this,
Many countries the phone system keeps current flowing in the wires all
the time, this is called "Sealing Current" and if you have the manual
for an old 300 or 1200 baud modem lying about you can read all about it.

The reason for this is to PREVENT line faults, believe it or not. As
well as instant detection of line faults.

Modern teletype (BAUDOT and later ASCII teletype machines) like the Type
15, 28 and 33 all used idle on MARK

One of the more interesting lengths of paper tape I used to have was
punched by one of the national news wires one November back in what,
1963 (The 23th as I recall) You play the tape and it starts typing out
routine items (I recall a farm report or some such but it's been many
years since I played the tape) then suddenly the machine runs "OPEN"
(Space) for a period and then the news flash.. Then it goes back to
routine and again it runs open.. the operator intruppted sends "Go Ahead
Dallas" and we read "The president is dead"

That's some tape.

On 4/15/2010 6:11 AM, David Griffith wrote:
I think the Mark and Space stuff has to do with the
fact that the line was always kept energized, thus, an idle line would
hold the sounder arm down. That way you'd know immediately if there was
a line fault. That would be a bit wasteful now, so I suppose I should
preceed each message with a very long dash to at least try to fake that
part.

The original Morse instrument was a device which used a scribe to
imprint a line on a paper tape which was moving past the scribe arm
under tension from a clockwork mechanism.

When the electromagnets were energized, the scribe would make a mark on
the tape. When they weren't, the tape would "space" past the scribe
point without being marked.

Ergo, "Mark" means current in the loop, "Space" means no current. The
early telegraphs were powered by batteries.

There is software available to do what you want to do: visit the Morse
Telegraph Club, http://www.mtc.org/ , for more information.

HTH.

73,

Bill W1AC

On Apr 15, 6:11 am, (David Griffith) wrote:
When the key is down, the sounder clicks down. Let go and
it clacks up. So, a dot is "click-clack" and a dash is
"click-wait-clack".

With most sounders, the sound of the armature going down is different
from the sound going up, as you describe, so it's more than the time
spacing.

I think the Mark and Space stuff has to do with the
fact that the line was always kept energized, thus, an idle line would
hold the sounder arm down. That way you'd know immediately if there wa
s
a line fault.

Yes, but there were several reasons for the normally-energized series
line systems.

1) The first systems were powered by wet primary batteries called
"gravity" cells. (You can still make your own - all you need is
copper, zinc, copper sulphate, water and a jar). Unlike most other
kinds of cells, the gravity cells need a load for best results.

2) The primary cells required a lot of maintenance and care. With a
normally-energized system, line batteries were needed only at the ends
of a line; the telegraph offices in between would not need them
(except a cell or two for local loops). A typical line battery would
consist of 100 to 200 gravity cells (often half the cells would be at
each end) and permit operation over lines of 100 to 400 miles,
depending on the wire size and number of intermediate stations. (#9 or
#6 iron wire was commonly used for telegraph lines). So you can see
the advantage of not needing line batteries everywhere!

3) Besides making a line break obvious, operation up to a break could
be had by grounding the line at the last convenient point before the
break.

4) Normally energized circuits made duplexing, multiplexing and other
systems easier to implement.

The wire telegraph was more sophisticated than some folks give it
credit for being.

----

A telegraph story:

There was a railroad which had an important position open at the
division office. Applicants were told to show up on a certain day in
the outer waiting room, and wait to be called into the
Superintendent's private office for an interview.

The outer waiting room was a busy place, with a telegraph sounder
going continuously, various employees doing all sorts of tasks, and
the Superintendent inside his private office with the door shut.

A number of applicants showed up, most with years of experience. Each
handed their papers to the clerk, took a seat, and waited.

After all the chairs were occupied, a young man arrived - obviously
not nearly so experienced as the others. He paused for a moment,
papers in hand. Then he walked straight to the door of the
Superintendent's private office, opened it, and walked right in,
closing the door behind him!

The other applicants looked at each other in surprise and some
amusement. Barging in on the Division Superintendent was the best
guarantee of never getting any job! One waiting applicant said the
word "greenhorn" and the others all nodded.

But a few moments later, the door of the Superintendent's office
opened, and the Superintendent came out, followed by the young man.
The Superintendent said: "Thank you all for coming, but the position
has been filled." It was obvious that the young man had gotten the job
they all wanted.

Some of the applicants started to protest, but the Superintendent just
pointed to the telegraph sounder. It wasn't on an outside line. It was
playing the same message over and over:

"If you can read this, come into my office"

73 de Jim, N2EY

The

N2EY wrote:

Yes, but there were several reasons for the normally-energized series
line systems.

Another thing is that telegraph "lines" might indeed be a single wire..
Using the Ground as the "Return" for the loop

This was often done both for telegraph and for mains electrical at one
time due to a shortage of metal for the wires... This is very likely why
house systems have a ground bonded to the neutral at the service
entrance AND AT THE POLE.. At one time they simply forgot to use a neutral.

Plus I"ve seen several "Loop" systems today where a single wire is
looped from the "Central office" out to each "node" or station and all
the way back.. One such was made by Phillips back in 1980.. I used to be
one of the operators (This was a telephone system) the finished product,
I used to joke, had one part that NEVER FAILED... That was a reset
button... The original failed and the replacement came from Radio Shack.

On Apr 16, 10:20 am, John from Detroit wrote:
N2EY wrote:
Yes, but there were several reasons for the normally-energized series
line systems.

Another thing is that telegraph "lines" might indeed be a single wire..
Using the Ground as the "Return" for the loop

It is my understanding that many of them were. Besides the savings in
wire and insulators, a ground-return system could actually be lower
resistance than a double-wire system if the "made grounds" at the ends
of the lines were very good.

Of course such a line is more vulnerable to noise, but since the wire
telegraph was a digital system the nouse would have to be considerable
to have any effect.

73 de Jim, N2EY

N2EY wrote:
On Apr 16, 10:20 am, John from Detroit wrote:
N2EY wrote:
Yes, but there were several reasons for the normally-energized series
line systems.

Another thing is that telegraph "lines" might indeed be a single wire..
Using the Ground as the "Return" for the loop

It is my understanding that many of them were. Besides the savings in
wire and insulators, a ground-return system could actually be lower
resistance than a double-wire system if the "made grounds" at the ends
of the lines were very good.

Of course such a line is more vulnerable to noise, but since the wire
telegraph was a digital system the nouse would have to be considerable
to have any effect.

That thing about noise reminded me of a story about a severe magnetic
storm that happened in the 1880s or thereabouts. Currents induced into
telegraph lines were so strong that things caught fire in telegraph
offices as well as simply knocking them offline.

--
David Griffith
--- Put my last name where it belongs

David Griffith wrote:
N2EY wrote:
On Apr 16, 10:20 am, John from Detroit wrote:
N2EY wrote:
Yes, but there were several reasons for the normally-energized series
line systems.
Another thing is that telegraph "lines" might indeed be a single wire..
Using the Ground as the "Return" for the loop

It is my understanding that many of them were. Besides the savings in
wire and insulators, a ground-return system could actually be lower
resistance than a double-wire system if the "made grounds" at the ends
of the lines were very good.

Of course such a line is more vulnerable to noise, but since the wire
telegraph was a digital system the nouse would have to be considerable
to have any effect.

That thing about noise reminded me of a story about a severe magnetic
storm that happened in the 1880s or thereabouts. Currents induced into
telegraph lines were so strong that things caught fire in telegraph
offices as well as simply knocking them offline.


Friend of mine hooked a very high impedance volt meter to his long wire
antenna one storm and got some very interesting voltmeter readings

Several volts (As in 3 digits) as I recall.. Of course it did not take
much current to ground it out but it was amazing the amount of voltage
on that wire.

My Long wire is DC-Grounded so I don't see that.