Earlier analogy communication is used to transmit the messages. It used lot of bandwidth and its efficiency is very less. Then to solve this problem, we shifted to digital communication. Now we are using digital communication everywhere, starting from TV to Mobile. The GSM standard which came into being from 1990 changed the way of mobile communication. With this we can directly talk to each other from any place in the world to any place, send messages and information faster, video chat etc. For an Electronic and Communication student and for a Communication specialization student, knowing about mobile communication and able to express it skilfully to a layman also is a task which is tougher than actually said.
Mobile phone is able to communicate even from a remote location if it has signal, have you ever wondered how these mobiles work? Mobile phone sends and receives data in the form of radio waves of very high frequency. When you dail a number from your mobile phone, your mobile phone which is already connected to the mobile tower sends this information to it. The mobile tower is connected to the Switching Centre. Switching Centre is a place which determines whether there is any route empty to send the signal to the tower which is having the receiver. If any line is not available it will tell the same to the dailer through IVRS, which many of us experienced many times. If the line is available, it initiates the process and sends the signal to the tower to inform the receiver about the phone call. The billing is also based on the duration of call in switching station records which is almost the same with dailer and receiver mobile handset records. Coming to Fixed Telephones or Landlines, instead of Radio signals they use optical cables or copper wires and instead of tower there will be a telephone link network; except these two the remaining procedure is same.
The switching centre uses two types of techniques – Packet switching or Circuit switching. In circuit switching, the whole message is transferred once where as in the packet switching the whole message is divided into different packets and at the receiver end reconstructed with the received packets. This not only improves speed but also improves the efficiency of the transmission lines.
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