Data Communications

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C e llp h o n e

Data Communications

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In te rn e t S u rfin g

Analog and Digital Data

Computer, music CD’s d, light, electricity, etc

Analog Transmission of Analog Data versus Analog Transmission of Digital Data *Phone call- voice is converted into analog signal by the transmitter *If you want to send digital data across an analog telephone circuit using a modem

Digital Transmission of Digital Data versus Digital Transmission of Analog Data *Transmission of data through a digital carrier circuit such as ISDN or T1 line (if you have than line, you can connect your digital phone to a digital line through a digital interface such as a NT1 or CSU/DSU *Analogphone call into a digital signal transmitted outside by the telephone company

Analog to Digital Conversion The principle by which the music CD’s are created When the artist sings, the sounds that are created and transmitted through the air are analog. However, when you listen to a music CD, the sounds that are reproduced originate from a digital recording.

Parallel and Serial Transmission Serial – transmit data bitafter-bit Parallel – transmit several bits Ex . ISA, sent ATA, SCSI,together PCI are Ex.8-bit at a time Although the data is going in one direction, the data is sent bit-bybit with serial communication (single lane road-car by car). With parallel the data is moved multi bits at a time (a multi lane highway going in the same direction with full of traffic)