1 / 4

Chapter 5 Asynchronous Communication

Chapter 5 Asynchronous Communication. Sender and receiver do not synchronize before data transmission Receiver does not know when individual bits begin and end. RS-232 Standard. Used in async serial transmission Eg. Dumb terminals, terminal server, analog modems, console ports

damia
Télécharger la présentation

Chapter 5 Asynchronous Communication

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 5 Asynchronous Communication • Sender and receiver do not synchronize before data transmission • Receiver does not know when individual bits begin and end

  2. RS-232 Standard • Used in async serial transmission • Eg. Dumb terminals, terminal server, analog modems, console ports • sender transmit character anytime • arbitrarily delay between characters • Binary 1 represented by –15 volts • Binary 0 represented by +15 volts • Idle voltage is –15 volts with minimum duration of one bit • Start bit (binary 0) sent before character • RS-232 voltage diagram (fig 5.2)

  3. RS-232 (cont.) • Baud rate • number of changes in the signal per second. • Bits per second may be equal to or greater than baud rate • Supports full duplex • DTE equipment (eg. computer) transmits on pin 2 and receives on pin 3 • DCE equipment (eg. modem) transmits on pin 3 and receive on pin 2 • Minimum 3 wires (fig 5.3) • DTR,DSR,DCD,RTS,CTS,TxD,RxD,GND • RTS/CTS used in hardware flow control

  4. Bandwidth • maximum rate (Hertz) that a transmission system can change a signal • Maximum theoretical data rate D (bits/s) for a transmission system with bandwidth B and uses K unique values of voltages: D = 2Blog 2 K (Nyquist’s theorem)

More Related