Data Communication and Networking (DCN) Practical External:-Presentation “Transmission Modes” Submitted To:- “Ms. Mansi Dangarwala” Submitted By:- Manaswi Sharma (185)
Data transmission is the physical transfer ofdata (a digital bit stream) over a point-to-point orpoint-to-multipoint communication channel.Communication channel is any physical medialike cables etc.
Transmitted simultaneously on separate wires. Multiple circuits for connection. Devices close to each other. E.g. Data transmission between computer and printer.
Advantages of parallel transmission: 1. Time required is only one clock cycle. 2. Clock frequency can be kept low.Disadvantages of parallel transmission: 1. Number of wires. 2. Too many wires.
Transmitted serially on same wire. Requires 1 wire to connect. Close or far doesn‟t create any problem. E.g. Data transmission between computer and computer.
Advantages of serial transmission: 1. Only one wire is required. 2. Reduced cost due to less number of conductors.Disadvantages of serial transmission: 1. Speed of data transfer is low. 2. To increase speed of data transfer, clock frequency needs to be increased.
In data communication, Timing control of the reception of bits is important. There are two methods of timing control for reception of bits.
Data bytes transmitted at any instant of time. One byte at a time. Ideal time between two bytes. Different clock frequencies. „start‟ and „stop‟ bits are used. Ideal time is not constant, also known as gaps. Timing of signal is not important.
Advantages of asynchronous transmission: 1. Synchronization not necessary. 2. Cheap scheme.Disadvantages of synchronous transmission: 1. „start‟ and „stop‟ bits and gaps makes transmission slow. 2. Timing error.
Carried out under common master clock. Transmitted as a block of bits. Operate at same clock frequencies. No „start‟ and „stop‟ bits required. No gaps between data bytes. Timing of signal is important.
Advantages of asynchronous transmission: 1. Speed of data is much. 2. Timing errors are reduced.Disadvantages of synchronous transmission: 1. Data entirely dependent on timing. 2. Devices should be properly synchronized.