Category:Telegraphy

Muirhead automatic telegraph syphon receiver, 1903

A system of telecommunication for the transmission of graphic symbols, usually letter of numerals, by the use of a signal code. Types include electrical, radio, and wireless.

For a history on the telegraph, see the Telegraph article.

Subcategories

• Electrical telegraphy - the long-distance transmission of messages or information via electrical signals, usually over telecommunications lines or radio
• Image telegraphy - the use of telegraphic signals to send scanned images, such as in a fax machine
• Morse telegraphs - the telegraphs created by Samuel Morse beginning in the 1830s, which were the first to allow electrical transmission of information over long distances
• Optical telegraphy - a system of conveying information by visual signals, usually using towers with flags or shutters
• Radio telegraphy - also known as wireless telegraphy, telegraphic signaling without wires connecting the end points of communication
• Semaphore telegraphs - a kind of optical telegraphy in which information is communicated through towers with moving moving arms whose position expresses symbols, today can also refer to flag semaphore systems
• Submarine telegraphy - telegraphy through the means of a cable laid on a sea bed
• Telegraph applications - the myriad potential uses of a telegraph system
• Telegraph transmission speed - also known as a "baud" after Emile Baudot, pulses or symbols per second
• Telegraph transmission technology - the devices and techniques used to transmit telegraph signals, such as coaxial cables
• Wireless telegraphy - an older name for radio telegraphy