Which two networking devices operate at Layer 1 of the OSI model? (Choose two.)

Which two networking devices operate at Layer 1 of the OSI model? (Choose two.)
A . Repeater
B . Bridge
C . Switch
D . Router
E . Hub

Answer: A,E

Explanation:

It defines the electrical and physical specifications of the data connection. It 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." http://en.wikipedia.org/wiki/OSI_model