Morse code by telegraph question

[Rocketeer]

How does Morse code sent by telegraph work? If, for instance, you wanted to send "U" (dot-dot-dash), would it sound like this:

click-click-(pause)-click?

or this:

click (short pause)-click(short pause)-click (long pause)-click ? (that is, do the pauses correspond to dots and dashes?)

[Colophon]

Neither. It would be:

bzt-bzt-bzzzt

In other words, the key would be pressed down for longer to make the dash.

You can see the trace from Morse's first telegraph message here (http://upload.wikimedia.org/wikipedia/commons/f/f1/The_First_Telegraph.jpg).

Transmission isn't limited to "clicks" - the signal is transmitted for as long as the key is held down.

[Lumpy]

I think you have it backwards. Morse is essentially a trinary code, with pauses the same length, dots a short click, and dashes a long click. (Although now that I think about it, how do you make a "click" longer? Makes more sense with beeps.)

ETA: what Colophon said.

[Rocketeer]

Ah, okay, I understand. I had thought that all a telegraph receiver could do was click; I didn't realize it could "buzz".

[UncleRojelio]

Ah, okay, I understand. I had thought that all a telegraph receiver could do was click; I didn't realize it could "buzz".

The early telegraphy used a sounder (http://en.wikipedia.org/wiki/Telegraph_sounder) that could only produce clicks and clacks. They also used the American Morse code (http://en.wikipedia.org/wiki/American_morse_code) which is different than the International Morse code used today.

[Kevbo]

The early telegraphy used a sounder (http://en.wikipedia.org/wiki/Telegraph_sounder) that could only produce clicks and clacks. They also used the American Morse code (http://en.wikipedia.org/wiki/American_morse_code) which is different than the International Morse code used today.

This is correct. The sounder has a slightly different tone when the coil energizes vs. when it releases. Click and clack is about as good as you can discribe it with words. It was not uncommon to add a plug tobacco tin to the sounder frame near the top stop screw to enhance this difference, as well as to give a different character to the sound for multiple sounders in one office, and make the sounder a bit louder.

International morse arose because undersea cables were unable to transmit the long dashes used in some American Morse characters. One polarity was used for dots, the other for dashes. The long cable lengths caused temporal distortion, so dots and dashes on such cables could not be distinguished by length.

Land line telegraphy hung on for a long time in railroad dispatching work long after telephones had replaced it in the general populace. When you need to transfer information with no alteration to a third party, (train orders) voice isn't really any faster than morse code...you have to spell out any unusual word, and can only go as fast as the recieving operater can write or type.

So to the OP:

The letter a (dot dash) would sound like

click_clack_click___clack

With only the underscores indicating elapsed time.

[Keeve]

I think you have it backwards. Morse is essentially a trinary code, with pauses the same length, dots a short click, and dashes a long click.Not trinary, but four-part. IIRC there were short pauses within a letter, and long pauses between letters.
So, for example, SOS (dot dot dot dash dash dash dot dot dot) was like this:

bzt _ bzt _ bzt _ _ _ bzzzt _ bzzzt _ bzzzt _ _ _ bzt _ bzt _ bzt

[Keeve]

And that's why, instead of adding another code for end-of-sentence, they used the word "stop".

[Rocketeer]

So SOS in railroad telegraphy would be

click-clack_click-clack_click-clack______click---clack_click---clack_click---clack_______click-clack_click-clack_click-clack?

[Exapno Mapcase]

So SOS in railroad telegraphy would be

click-clack_click-clack_click-clack______click---clack_click---clack_click---clack_______click-clack_click-clack_click-clack?

No. In your writing: click -- click -- click ---- clack -- clack -- clack ---- click -- click -- click.

Or what Keeve already wrote.

Why are you doubling each sound?

[Ximenean]

People have successfully sent Morse code using effectively binary signalling devices, such as banging on pipes, and yes, the length of the pause after the sound indicates whether it's a dot or a dash. It does introduce some ambiguity, and so requires some guesswork on the part of the decoder. A message UUU (no spaces) would sound very much like S S S (with spaces).

[Acsenray]

Perhaps the source of the confusion is that someone standing next to a telegraph operator would hear only the clicks. You'd have to put on the headphones to hear the actual content.

[UncleRojelio]

So SOS in railroad telegraphy would be

click-clack_click-clack_click-clack______click---clack_click---clack_click---clack_______click-clack_click-clack_click-clack?

Well, I don't know why a railroad telegrapher would send 'SOS', but if for some reason he did, the American Telegraph code for 'O' is '.-.', not '---'.

[UncleRojelio]

No. In your writing: click -- click -- click ---- clack -- clack -- clack ---- click -- click -- click.

Why are you doubling each sound?

Because the sounder has to return after every 'click', resulting in a 'clack.' You can't have a 'click' without a 'clack' and vice-versa.

[UncleRojelio]

Perhaps the source of the confusion is that someone standing next to a telegraph operator would hear only the clicks. You'd have to put on the headphones to hear the actual content.

We are talking about a form of telegraphy used before headphones came into use. The clicks and clacks would have been coming from a mechanical device sitting out in the open. It didn't have a headphone jack on it and didn't generate a signal that could be heard via headphones in first place.

[Acsenray]

What era of telegraphy are we talking about?

And are you saying that there wouldn't be any buzzing? I seem to recall playing with old telegraph thingies that buzzed. The clicking sound was made by the operator, but that's not what the receiver listened for.

[UncleRojelio]

What era of telegraphy are we talking about?

And are you saying that there wouldn't be any buzzing? I seem to recall playing with old telegraph thingies that buzzed. The clicking sound was made by the operator, but that's not what the receiver listened for.

We are talking about he era of the Electrical Telegraph (http://en.wikipedia.org/wiki/Electrical_telegraph). The more familiar buzzing telegraphs came along when wireless was invented.

[Rocketeer]

Well, I don't know why a railroad telegrapher would send 'SOS', but if for some reason he did, the American Telegraph code for 'O' is '.-.', not '---'.

Oops. But am I right otherwise?

And presumably with wireless telegraphy (International Morse), it'd be

ditditdit_buzzbuzzbuzz_ditditdit?

[whitetho]

So SOS in railroad telegraphy would be

click-clack_click-clack_click-clack______click---clack_click---clack_click---clack_______click-clack_click-clack_click-clack?Officially it's not "SOS", it is the Morse code distress signal, which instead of three separate letters, actually is three dots/three dashes/three dots all run together. Thus, it would be click-clack_click-clack_click-clack_click---clack_click---clack_click---clack_click-clack_click-clack_click-clack.

The distress signal is known informally as "SOS" because in International Morse S is three dots and O is three dashes. However, in American Morse, which an oldtime U.S. operator would use, while S is still three dots, three dashes stand for the numeral five, so, again informally, the distress signal was known as S5S. See, for example, the 1910 article "S 5 S" RIVALS "C Q D" FOR WIRELESS HONORS (http://earlyradiohistory.us/1910S5S.htm).

[UncleRojelio]

And presumably with wireless telegraphy (International Morse), it'd be

ditditdit_buzzbuzzbuzz_ditditdit?

If you want to say it out loud, the convention would be: di di dit dah dah dah di di dit.

[Kevbo]

Why are you doubling each sound?

Each element is a click-clack with the time between the click and clack indicating a dot or dash.

A telegraph sounder is constructed a lot like a typical electro mechanical relay, but without the contacts. It wouldn't sound right, but a contactor (big honkin' relay) would make a usable telegraph sounder.