In the basic communication process, a sender puts a message in words and transmits it to a receiver who interprets the message. The medium the sender chooses to transmit the message is called the communication channel.
So, Letter, e-mail telephone are examples of Channel.
Traditional telephone lines typically carry analog signals.
When we speak on a traditional landline phone, our voice (which is analog) is converted into electrical signals that travel through the telephone wires.
These analog signals are then transmitted over the telephone network.
