Telegraph model.
Everything else not included in the sectionsInterphone devicesThe telegraph model was produced presumably since 1955 by the Glavuchtekhprom of the Ministry of Education of the RSFSR. The demo telegraph model allows receiving Morse code signals by connecting a telegraph key and a direct current source with a voltage of 4 volts. When you press the key, the circuit closes and an electromagnet is triggered pulling a lever, at the long end of which a pencil is fixed, which, depending on the duration of pressing the key, draws short or long strips on the paper tape. The belt is manually driven.
