(i) Simplex (ii) Half-duplex (iii) Full-duplex

Signals are usually transmitted over some transmission media that are broadly classified in to two categories

Guided Media: These are those that provide a conduit from one device to another that include twisted-pair, coaxial cable and fiber-optic cable. A signal traveling along any of these media is directed and is contained by the physical limits of the medium. Twisted-pair and coaxial cable use metallic that accept and transport signals in the form of electrical current. Optical fiber is a glass or plastic cable that accepts and transports signals in the form of light

Unguided Media: This is the wireless media that transport electromagnetic waves without using a physical conductor. Signals are broadcast either through air. This is done through radio communication, satellite communication and cellular telephony

Transmission is a physical movement of information and concern issues like bit polarity, synchronization, clock etc

Communication means the meaning full exchange of information between two communication media

Network

ARP