The blank paper tape was fed in from the right over a roller and came out the left side. It was oriented in a vertical plane. The paper punches were labelled with numbers: 1 for the top hole of the dot, 2 for the sprocket hole for dot, and 3 for the bottom hole for dot. When a dash was punched, extra hole punches to the right punched a centre hole with number 4 and a bottom hole with number 5. The perforator was introduced in 1867. It enabled transmission speeds on a telegraph line to increase to 70 words per minute. The very first message ever punched onto a tape was "SOS EIOS". The manual perforator was subsequently replaced by keyboard perforators like the Gell keyboard perforator or Kleinschmidt keyboard perforator. Each of the keys had a spring to restore its position after pressing. Each key moved a corresponding lever underneath the instrument. The other end of the levers protruded up into the back of the mechanism. Each punch rod also had a spring to put it back in place after punching a hole. For space and dot keying (A or A1) the star wheel was only allowed to turn one position by a pawl, and the paper tape only moved forward one position. However, when key A2 was hit, the corresponding lever B2 raised a bar (h) which allowed another lever attached to the pawl to move further back when the star wheel rotated, and the wheel could turn two positions, for a dash. The distance the paper tape moved for each position was determined by how far lever k moved, and its range of movement had to be set by adjusting screws i and t. A flat spring g stored energy from the punch to move the paper. The force of the spring was determined by adjusting screws n and n'. A guide roller (r) with a groove was pressed by an adjustable spring to press the pawl against the star wheel. The star wheel was on a frame with a piece sticking out the left hand side as a lever. When the operator wanted to insert paper tape, this lever was pulled, and the star wheel retracted from the paper. The Wheatstone transmitter read a paper tape (Wheatstone slip) and converted the dot pattern into mark and space symbols on the telegraph line. It worked by two rods alternately rising up to sample the holes in the tape. 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.