Disadvantages Of Serial Transmission Rates

Serial transmission • 1. Serial Transmission & Synchronization Mukesh Patel School of Technology Management and Engineering • Content Transmission mode Parallel transmission Serial transmission Synchronous transmission asynchronous transmission • Transmission mode A given transmission on a communications channel between two machines can occur in several different ways. The transmission is characterized by:  the direction of the exchanges.  the transmission mode: the number of bits sent simultaneously simultaneously.  synchronization between the transmitter and receiver. • The direction of the exchanges There are 3 different transmission modes characterized according to the direction of the exchanges.

 Simplex  Half Duplex  Full Duplex • Simplex Mode  In simplex mode the communication is uni-directional as on a one-way street.  Only one of the two stations on a link can transmit, the other can only receive.

This article will contrast the three methods and highlight some of their advantages/disadvantages. Serial data transmission used for short-distance between boards.

 Examples: Keyboard, Monitor, Mouse • Half Duplex  In half-duplex mode, each station can both transmit and receive but not at the same time.  When one device is sending, the other can only receive.  The half-duplex mode is like a one-lane road with two-directional traffic.  The entire capacity of the communication channel is taken over by whichever of the two devices is transmitting at the time. Walkie-talkie • Full duplex  In full-duplex mode both stations can transmit and receive simultaneously.  The full duplex mode is like a two-way street with traffic flowing in both directions at the same time.

 In full duplex mode signals going in either direction share the capacity of the link.  This sharing can occur in two ways either the link must contain two physically separate transmission paths, one for sending and the other for receiving or the capacity of the channel is divided between signals traveling in opposite directions. • Data Transmission-Modes • Parallel Transmission Binary data, consisting of 1’s and 0’s,may be organized in to groups of n bits each. Computers produce and consume data in groups of bits. By grouping we can send data n bits at one time.

Each bit has its own wire. N bits of one group can be transmitted with each clock tick from one device to another. • Parallel Transmission • Serial Transmission In serial transmission one bit follows another, so we need only one communication channel instead of n to send n bits. The advantage of serial over parallel transmission is that with only one communication channel. Serial transmission reduces the cost of transmission over parallel roughly by a factor of n. Communication within devices is parallel, conversion devices are required at the interface between the sender(parallel-to-serial) and receiver (serial-to- parallel). • Serial Transmission • Serial Transmission  Serial transmission can occur in one of two ways.

Eminem marshall mathers rar blogspot themes. Synchronous Asynchronous • Synchronous Transmission In synchronous transmission, the bit stream is combined in to longer frames which may contain multiple bytes. Each byte is introduced on to the transmission link without a gap between it and the next one. It is left to the receiver to separate the bit stream in to bytes for decoding purposes. Timing is important in synchronous transmission • Synchronous Transmission • Advantages of synchronous transmission The advantage of synchronous transmission is speed. Byte synchronization is accomplished in the data link layer. • The start and stop bits in each frame of asynchronous format represents wasted overhead bytes that reduce the overall character rate.

These start and stop bits can be eliminated by synchronizing receiver and transmitter. Receiver and transmitter can be synchronized by having a common clock signal as shown in above fig. Synchronous Transmission • Serial In - Serial Out Shift Registers • A basic four-bit shift register can be constructed using four D flip- flops, as shown below.