Talk:Electrical telegraph

message: In the spirit of a brief review, here are some things I noticed that the article could use.  The history is excellent, but there is no "How it works" section describing the science of how an electric telegraph line works, giving a typical circuit diagram, and such details as an explanation of "dots" and "dashes", duplex operation, "break-in" signaling, Q-codes, Continental vs American Morse, telegram format and prices.  There are images of some early historical systems, but few images of the mature widely used technology of the latter 1800s.  There are two redundant images of paper tape recorders at top, only one image of a primitive key, not a standard Morse key, and no images of the other important components of a telegraph line - the liquid battery, relay, telegraph sounder, telegraph pole, telegraph office and telegram form.  I'm working on other articles now but could probably contribute at some future date.  However I don't really know much. --ChetvornoTALK 14:41, 20 July 2018 (UTC)
thread_title:  Some things the article needs 

message: Montgomerie may be notable.  See this and this scholar search.  If you are going to remove redlinks, at least give a rationale why the subject is not notable.  If you don't, people will think you have not read Wikipedia:Red link. SpinningSpark 23:56, 23 November 2018 (UTC)
thread_title:  Montgomerie 

message: I have removed the mention of Alter's telegraph.  As far as I can tell, nothing was published or reported at the time this telegraph was supposed to have existed.  The story is entirely anecdotal, coming to light long after the rise of the telegraph.  Ok, there are some claimed witnesses, but the story is still "Oh yes, I built one of those in my barn once".  Yeah, and I built an electronic computer in my bedroom in the 1950s (or tried to).  It's an extraordinary claim, so needs more scholarly sources than an interview in Popular Science.  In any case, even if perfectly true, it had no effect whatsoever on the development of the telegraph since no-one actually involved in the development had heard of it.   At best, it is tangential to the story. SpinningSpark 09:58, 16 December 2018 (UTC)
thread_title:  Alter's telegraph 

message: has disputed that telegraph lines are inherently half-duplex.  Just in case there is confusion here:
# Simplex - communication proceeds in one direction only
# Duplex - communication can proceed simultaneously in both directions
# Half-duplex - communication can proceed in both directions, though not at the same time.
Examples: (1) broadcast radio, (2) telephones, (3) "walky-talky" type radios.
Next, what is meant by a "line"?  A communications path might consist of several wires, such as the Wheatstone system, or a single wire such as the classical Morse system.  In the latter case signalling is always simplex or else half-duplex using a "turn-around" character (think of radio operators using the proword "over").  The only mechanism to permit full duplex operation would be modulation of carrier waves, and I'm not aware that telegraph systems ever used this (though could be proved wrong).  Regards, Martin of Sheffield (talk) 15:43, 20 July 2019 (UTC)
replies: text: You certainly can be proved wrong.  See Quadruplex telegraph.  Bare copper wire lines are not inherently half-duplex.  I would have thought that was obvious. Your example #2 shows that. SpinningSpark 15:50, 20 July 2019 (UTC)
replies: text: But that's a half-duplex system.  For the duplex part consider that the current can only be flowing in one direction at any instant.  The Stearns part stops the local receiver responding to the local key, but to activate the remote receiver current must be passing from local to remote.  The utility of the system was not to permit simultaneous transmission which would be difficult for an operator to handle, but to allow recording mechanisms to just record inbound traffic.  The diplex part relies on using opposite polarities.  Consider what happens if local A holds the line positive and local B is trying to pull the line negative. Martin of Sheffield (talk) 16:07, 20 July 2019 (UTC)
replies: text: Every source I have ever read on the quadruplex telegraph says that four messages (two in each direction) can be sent simultaneously.  See for instance Bray, Innovation and the Communications Revolution.  Please provide a source for your claim.  In any case, quadruplex notwithstanding, duplex telegraphs were in existence prior to Edison's invention. It is an utterly standard analysis of transmission lines to consider two currents flowing simultaneously on a line representing signals travelling simultaneously in opposite directions.  No carrier wave modulation is required to either generate such signals or to separate them. SpinningSpark 17:13, 20 July 2019 (UTC)
replies: text: I'm suprised that you gave a link to chapter 6.  The first paragraph mentions duplex and quadruplex systems just in passing, the whole of the rest of the chapter is "The telegraph-telephone frequency-division multiplex transmission engineers"!  The first two paragraphs of section 3.3 would have been a better quote, but even then it rapidly leads to Baudot and his time-division multiplexing.  As regards a source, you provided one - Quadruplex telegraph.  Early telegraphs worked at slow speeds over relatively short distances, a DC analysis is therefore more appropriate than a transmission line analysis using step functions or AC theory.  According to Morse_code#User_proficiency the fastest keying ever recorded was 35 wpm.  Using a 50 dot duration word that comes out at around 30 baud.  Assuming 1 baud = 1 Hz, that is a wavelength of 10,000 km. Martin of Sheffield (talk) 19:37, 20 July 2019 (UTC)
replies: text:  I could cite any number of books that say the same thing. Do your own gbooks search if you doubt it.  The bottom line is that your addition has been challenged.  Per WP:V you need to cite a source before it can go back in (and one that has more authority than all the dozens of sources that contradict your claim – which does not include a Wikipedia article, even if I accepted that it supported you, which I don't).  Arguing from your own analysis doesn't cut it if you don't have a source to back it up. SpinningSpark 13:31, 26 July 2019 (UTC)
replies: text: I thought you'd given up arguing this.  Before I waste more time, perhaps you could explain "The bottom line is that your addition has been challenged.  Per WP:V you need to cite a source before it can go back in", since the only time I've edited the article was a clarification on Morse.  The reference to the Wiki article is that it clearly explains the mechanism, have you read it in detail?  Martin of Sheffield (talk) 14:40, 26 July 2019 (UTC)
replies: text:  My apologies, it was not you who inserted the text.  I was discussing the text I removed here which is the same edit you were referring to in your opening post.  However, that does not change the position that a reliable source is required before it could go back in.  I don't care what it says on the quadruplex telegraph page, we don't accept other Wikipedia articles as reliable sources, but in any case, nowhere on that page does it say that the system is not true duplex. SpinningSpark 16:46, 26 July 2019 (UTC)
thread_title:  Half-duplex 

message: First of all, congratulations to Chetvorno for providing a badly needed much better, and more detailed lead.
I have extensively reworked the second paragraph for two reasons. Firstly to get it into historical order; needle telegraphs came first by a wide margin and remained important in the UK, British Empire, and France for some time, even after the Morse system became widespread.  Secondly, it was too Morse-centric, especially after Mark's additions.  Certainly, the Morse system is important, but the little details of the way the Morse system worked don't belong in the lead of this article.  They belong in an article on the Morse system which Wikipedia currently sorely lacks.  The Morse code article stands in for this lack with redirects, but the code is not the same thing as the system.
Thanks again to Chetvorno for something that should have been done a long time ago. SpinningSpark 16:44, 20 July 2019 (UTC)
thread_title:  New lead 

message: I think the Wheatstone ABC telegraph has been given WP:UNDUE prominence in this article.  It has more words written than both the Cooke & Wheatstone, and the Morse systems.  It was basically a minor sideshow compared with the latter two.  As far as I know, it was never used in public telegraph offices, it was entirely for private use.  There are other systems that were much more widespread that aren't mentioned at all.  The Henley-Foster telegraph and the Foy-Breguet telegraph are examples that were taken up by major organisations.  Also, it has been inserted under the Cooke and Wheatstone heading, but it never was an offshoot of the Cooke and Wheatstone system.
I propose that the material is cut out into a separate article, leaving just a mention and a link. SpinningSpark 16:52, 25 August 2019 (UTC)
thread_title:  Wheastone ABC telegraph 

message: I removed this recent addition from the article,
Orders were issued from Washington by telegraph, and newspapers used the telegraph to distribute news of the war, but I'm seeing no evidence that there was a telegraph connection to the front, let alone mobile telegraph wagons, or any actual use in war. This book says the nearest telegraph office to the front was at Richmond, Virginia, and it was horse rider relays from there.  This book says news stories were sent out by steamer from New Orleans. SpinningSpark 21:48, 12 November 2019 (UTC)
thread_title:  Mexican-American war 

message: If Repeater (disambiguation) does not really belong in Electrical telegraph#See also then you could have put it at the beginning of the article as a hat note as there are many kinds of relays. Peter Horn User talk 13:27, 15 September 2020 (UTC)
replies: text: Yes, there are many kinds of relay, but "electrical telegraph" isn't one of them so it's not an ambiguous term and doesn't need a hatnote. SpinningSpark 15:24, 15 September 2020 (UTC)
replies: text: But does it not incorporate either relays or repeaters? Peter Horn User talk 23:38, 15 September 2020 (UTC)
replies: text: A telegraph system incorporates lots of things – batteries, wires, sounders etc – but that does not mean that a disambiguation hatnote is needed.  We only disambiguate when the title of the article is ambiguous; see Wikipedia:Disambiguation.  It doesn't need to be in see also either since it is already discussed and linked in the article.  Relays are not even an essential part of a telegraph line.  They telegraph became a commercial proposition with them, but there were plenty of early telegraphs built without them. SpinningSpark 15:32, 16 September 2020 (UTC)
replies: text: Yeah, it certainly doesn't need a hatnote. --ChetvornoTALK 19:11, 16 September 2020 (UTC)
thread_title:  Repeater (disambiguation) 

message: The ASR-33 picture in the teleprinter section seems a bit anachronistic since that model was introduced in 1963 while the other stuff in the section is much older.  Should the ASR-33 pic be replaced with an earlier model?  I'm not too up on what was what in that era, but such things certainly existed.  2602:24A:DE47:BA60:8FCB:EA4E:7FBD:4814 (talk) 02:05, 8 August 2021 (UTC)
thread_title:  ASR-33 picture 

message: I think we need to be careful not to overstuff this article with pictures.  The text is starting to look cramped in places.  I know we always want pictures of everything, but this broad scope article covers so much different equipment we won't be able to put everything in. SpinningSpark 11:24, 15 August 2021 (UTC)
replies: text: Maybe, but in this case, I think the pictures really do aid understanding. --TedColes (talk) 13:38, 15 August 2021 (UTC)
thread_title:  Images