There are two types of communication channels
- Point to point channel
- broadcast channel
1. Point to point channel
Wire links, microwave links and optical fibers wire line operated by guided EM waves and they are used for local telephone transmission. In case of microwave link, the transmitted signal is radiated as an EM wave in free space microwave links are used in long distance telephone transmission optical fiber has low losses and used in optical communication.
2. Broadcast channel
It provide a capability where several receiving stations can be reached simultaneously from a single transmitter. An example is satellite is geostationary orbit, which covers about one third of the earth’s surface.