Page 161 - PYTHON-12

(b) Digital or Baseband Transmission

• No special device for conversion of signal to be transmitted over baseband medium.
• The signal is a group of discrete electrical units which is transmitted in rapid succession.
(c) Parallel Communication

• When data is transmitted through multiple wires with each wire carrying each bit, it is
called parallel communication.

(d) Serial Communication
• When bits are sent one after another in a series along a wire, it is called serial
communication.
10001----------------10001

(e) Synchronous or Asynchronous Transmission
• When sender and receiver synchronize their checks before transmission, i.e., the sender
first sends control characters to the receiver and then sends the actual data, it is called
synchronous transmission.

Advantage—Faster than asynchronous mode.
Disadvantage—Costly and complex set-up required.
• In asynchronous transmission, data is preceded and succeeded by a start bit and stop
bit respectively. No synchronization is required.

Advantage—Hardware required is simple and cheap.
Disadvantage—Slower than synchronous mode.

8.7 DIFFERENT WAYS OF SENDING DATA ACROSS NETWORK

There are several ways of sending data from one node to another through network. It can be in the
form of calls, messages, etc. By using various types of switching techniques, we can establish the
connection/communication.
8.7.1 Network Switching

A network is made up of several interconnected nodes. There can be a point-to-point connection or
star topology between pairs of devices, but both are not relevant for a large network. Hence, various
switching techniques are used to transfer packets of data from one port of a node to another. A
switched network is made up of a series of interconnected nodes called switches.
8.7.2 Switching Techniques

The main goal of networking is the reliable exchange of data or information among several
interconnected nodes. For the delivery of data with accuracy, various types of switching techniques
are used, namely:
Computer Networks
1. Circuit Switching
2. Packet Switching
3. Message Switching

8.7