Wheatstone system

[1] The system included a perforator, which prepared punched paper tape called a Wheatstone slip, a transmitter that read the tape and converted the symbols into dots and dashes encoded as mark and space electric currents on the telegraph line, and a receiver at the other end of the telegraph line that printed the Morse symbols.

The Wheatstone slip was a paper tape that contained holes in a pattern to control the mark and space signals on the telegraph line.

The middle row forms a rack so that a star wheel can move the paper forward.

Each vertical column represents a time interval in the Morse code, including the spacing between the holes.

The Wheatstone perforator was a development of Alexander Bain's 1848 manually operated hole punch machine for his "fast telegraph".

The keys were so difficult to press that fist-held rubber-tipped mallets were used to depress them and operate the punches.

The star wheel was on a frame with a piece sticking out the left hand side as a lever.

First of all the top hole was probed, and if the rod could go through, it moved a compound lever that connected the mark signal to the line.

The Wheatstone receiver converted the signal on the telegraph line to an inked pattern on a paper strip.

An electromagnet electrically connected to the telegraph line moved an inking wheel to press against the paper.

Paper spools were stored in drawers beneath the reader to allow quick change when one was exhausted.

These could be connected in parallel or series to achieve a 50 or 200 ohm resistance, to better match the telegraph line.

[9] The Wheatstone telegram consisted of strips of paper tape with the Morse code printed on it, pasted on a form.