CCNA Data Center Question of the Week: Layer 1 of the OSI Model

Answer: A and E.

Layer 1 defines the electrical and physical specifications of the data connection. It also defines the relationship between a device and a physical transmission medium (e.g. a copper or fiber optical cable). This includes the layout of pins, voltages, line impedance, cable specifications, signal timing, hubs, repeaters, network adapters, host bus adapters (HBA used in storage area networks) and more.  A repeater and hub (multiport repeater) just regenerate the signal from the ingress to the egress (or out all ports of a hub), with no interpretation of the meaning of the ones & zeros.