The punched paper tape (prepared with the SL b keyboard perforator) is inserted in the transmitting head of the transmitting unit, so that the first hole of a line is on top and the second hole is below the transport holes; the operating instructions recommend to mark the beginning of the paper tape with an arrow.
The punched paper tape is transported through the transmitting head. The polarised telegraph relay will close the circuit, when the rear contact pin in the transmitting head will give contact, and it will open the circuit, when the front contact pin makes contact (because there are two opposite holes coding a dot). In case of a dash with two diagnonal holes, the circuit is closed when the rear pin makes contact, the paper tape will be transported one step until the front pin makes contact and the circuit is opened, so a longer signal (a morse code "dash") is generated.
The transmitter GS 200b can be equipped with two different transmitting heads. Transmitting head A is used for morse code practise with 20 - 200 CpM speed and transmitting head B was intended to be used for high speed telegraphy with speeds of 100 - 900 ZpM, the transmitting speed can be regulated