File Name: transmission of digital data interfaces and modems .zip
- Chapter6(Interfaces and Modem)
- The DTE/DCE Physical Interface
- Data Transmission – Parallel vs Serial
- Digital Transmission
Data can be represented either in analog or digital form. The computers used the digital form to store the information.
Chapter6(Interfaces and Modem)
Data transmission and data reception or, more broadly, data communication or digital communications is the transfer and reception of data a digital bitstream or a digitized analog signal  over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires , optical fibers , wireless communication channels, storage media and computer buses. The data are represented as an electromagnetic signal , such as an electrical voltage , radiowave , microwave , or infrared signal. Analog or analogue transmission is a transmission method of conveying voice, data, image, signal or video information using a continuous signal which varies in amplitude, phase, or some other property in proportion to that of a variable. The messages are either represented by a sequence of pulses by means of a line code baseband transmission , or by a limited set of continuously varying waveforms passband transmission , using a digital modulation method. The passband modulation and corresponding demodulation also known as detection is carried out by modem equipment.
The DTE/DCE Physical Interface
Digital Data Transmission contd t Parallel Transmission By grouping, we can send data n bits at a time instead of one. Digital Data Transmission contd t Serial Transmission one bit follows another. Digital Data Transmission contd t Asynchronous Transmission send one start bit 0 at the beginning and one or more stop bits 1 at the end of each byte eg the connection of a terminal to a computer cheap and effective. Asynchronous here means asynchronous at the byte level, but the bits are still synchronized; their durations are the same. It is the responsibility of the receiver to group the bits The receiver counts the bits as they arrive and groups them in eight-bit units. DTE-DCE Interface contd t sending the data To be recognized as data, the amplitude of a signal must fall between 3 and 15 volts or between 3 and 15 volts. Function Shield Secondary receive ready Secondary send data Secondary receive data Signal ground Receive common Secondary request to send Secondary clear to send Send common.
Download as PPT, PDF, TXT or read online from Scribd. Flag for Inappropriate Transmission of Digital DATA: Interfaces and Modems.
Data Transmission – Parallel vs Serial
Digital Data Transmission contd t Parallel Transmission By grouping, we can send data n bits at a time instead of one. Digital Data Transmission contd t Serial Transmission one bit follows another. Digital Data Transmission contd t Asynchronous Transmission send one start bit 0 at the beginning and one or more stop bits 1 at the end of each byte eg the connection of a terminal to a computer cheap and effective.
A modem also receives modulated signals and demodulates them, recovering the digital signal for use by the data equipment. Modems thus make it possible for established telecommunications media to support a wide variety of data communication, such as e-mail between personal computers , facsimile transmission between fax machines, or the downloading of audio-video files from a World Wide Web server to a home computer.
Understanding T1 and E1 Interfaces. Example: Configuring a T1 Interface. Example: Deleting a T1 Interface. T1 and E1 refer to the data transmission formats that carry DS1 signals across interfaces.
It can operate at data rates from bps to 64Kbps. A second standard, X. It should perhaps be emphasized here that V24 defines the data terminal equipment interface to the modem and is not concerned with the interface between the modem and the line itself. The modems themselves therefore form part of the conceptual physical connection. The V24 interface is thus independent of both modulation technique and data throughput rate. The X. The control of the ensuing data transfer is the responsibility of the link layer.