Pointer telegraph
Charles Wheatstone constructed the first pointer telegraph in 1839; In this device, a hand driven by a clockwork could be stopped at will by an escapement device attached to the armature of an electromagnet from the remote departure station in front of each of the letters recorded on the edge of the dial.
The Mannheim engineer William Fardely built the first telegraph line on the European mainland in 1844, a 8.8 km long route between Wiesbaden and Kastel .
In 1846 August Kramer built an improved version, which was manufactured industrially in the following year by Werner Siemens and Johann Georg Halske and founded the company history of Siemens ; The Siemens pointer telegraph was used from 1848 on what was then the longest European telegraph line from Berlin to Frankfurt am Main .
Communication technology was revolutionized with the pointer telegraph ; In contrast to the Morse telegraph , the pointer telegraph also made it possible for an untrained layperson to transmit text messages for the first time . The pointer telegraph is a forerunner of the teleprinter .
The old optical telegraph also worked with pointers, but they are fundamentally different from a pointer telegraph.
functionality
The device is based on a pointer that is set manually; an adjustment of the pointer in the sending device leads to a corresponding adjustment of the pointer in the receiving device; in this way, the individual letters of a text can be transmitted in an uncomplicated manner without having to code them into Morse code first, for example .
Werner von Siemens reported in a letter to his brother Wilhelm in 1847: “My telegraph only needs a wire, can be played with keys like a piano and is so fast that you can telegraph almost as quickly as the keys pressed one after the other. It is ridiculously simple and completely independent of the strength of the current. "
Web links
Individual evidence
- ↑ Courage and inventive talent - the Siemens success story begins with the pointer telegraph. Siemens Historical Institute, accessed June 6, 2019 .
- ^ Feldenkirchen, Wilfried (ed.): WERNER VON SIEMENS - LIFE REMINDER. Piper Verlag, Munich 2008, p. 10