Here are some interesting links related to telegraphy.
Some books
*“The Electromagnetic Telegraph” by J.B. Calvert
http://mysite.du.edu/~jcalvert/tel/morse/morse.htm
*”Distant writing” from Steven Roberts
http://distantwriting.co.uk/
Some websites
www.telegraphlore.com from Greg Raven
http://atlantic-cable.com/ from Bill Burns
http://w1tp.com/ from Tom Perera
http://www.telegraph-history.org from John Casale
http://www.telegraph-office.com/ from Neal McEwen
http://telegraphmuseum.org/.. Porthcurno telegraph museum
http://www.sparkmuseum.com from John Jenkins
http://www.zianet.com/sparks/index.html from Russ Kleinman
http://www.n7cfo.com/ from Lynn Burlingame
http://www.vibroplexcollector.net/ from Randy Cole
http://www.telegraphkeys.com/ from Doug Palmer
https://australiantelegraph.wordpress.com/contents/ from Ron McMullen
http://www.civilwarsignals.org/ from the Signal Corps Association (USA)
http://www.morsetelegraphclub.com/ from the Morse Telegraph Club (USA)
And there is also my first website with (only) images of my telegraphs and some other apparatus:
http://www.telegraphsofeurope.net/ > courtesy of Greg Raven.
>>> Please let me know if you want to add yours and/or other interesting ones.