Telecommunications Overview; the OSI model of an IP computer network; concept of packets and frames; routing, access to the transmission channel and physical layer, in particular for the latter, baseband and modulation transmission. Importance of telecommunications in smart grids: an example of transmission will be studied more in detail (power line communications, SCADA, LoRAWAN, NB-IoT, ...). Importance of communications by a fieldbus in a car: an example of a bus will be studied more in detail (CANOpen or Modbus or Fieldbus or ....).