331: STUDY DATA COMMUNICATIONS AND NETWORKS

 1. Discuss computer networks (5 hrs)  2. Discuss data communications (15 hrs)

 PERFORMANCE STANDARD ◦ Given a network system, identify and illustrate the different data communications components clearly  Objectives: ◦ Define elements of a communication system ◦ Define data communications ◦ Discuss various types of transmission media and their characteristics ◦ Discuss encoding of information for transmission ◦ Discuss types of signal & their characteristics ◦ Relate data capacity of a channel and bandwidth ◦ Classify media based on bandwidth ◦ Discuss channel organization

Classify media based on bandwidth

 Bandwidth (BW) is that portion of electromagnetic spectrum occupied by a signal.  It is also the frequency range over which a receiver operates.  Wider bandwidth means more data can be transmitted  More specifically, bandwidth is the difference between the upper and lower frequency limit of the signal. BW=upper frequency-lower frequency

 Ex:  A common used frequency range is 300Hz to 3 MHz. What is the width of this band? f1=300Hz;f2=3MHz; BW=f2-f1 BW= BW=2.7MHz

 Try it yourself; A television signal occupies a 6 MHz bandwidth. If the low frequency limit channel 2 is 54MHz, what is the upper frequency limit? Ans: 60MHz

CategoryBandwidthData RateDigital/AnalogUse 1very low< 100 kbpsAnalogTelephone 2 < 2 MHz2 MbpsAnalog/digitalT-1 lines 3 16 MHz 10 MbpsDigitalLANs 4 20 MHz 20 MbpsDigitalLANs MHz 100 MbpsDigitalLANs 6 (draft) 200 MHz 200 MbpsDigitalLANs 7 (draft) 600 MHz 600 MbpsDigitalLANs

Category 3 Class C Category 5 Class D Category 5E Category 6 Class E Category 7 Class F Bandwidth16 MHz100 MHz 200 MHz600 MHz Cable TypeUTPUTP/FTP SSTP Link Cost (Cat 5 =1)

 Limited distance  Limited bandwidth (1MHz)  Limited data rate (100MHz)  Susceptible to interference and noise

 Compared to twisted-pair, coax provides greater bandwidth, and it also offers greater bandwidth for each channel.  Because it has greater bandwidth per channel, it supports a mixed range of services. Voice, data, and even video and multimedia can benefit from the enhanced capacity.

 Single Mode Fiber Optic Cable ◦ At distances up to 3 km, single mode fiber will deliver data rates up to 10 Gbps with a bandwidth of 20Ghz. ◦ Single mode fiber's primary uses are full motion video and any applications requiring extremely high bandwidth.

 Multimode Fiber Optic Cable ◦ It can deliver data rates up to 1 Gbps. ◦ For distances of 100 m or less, the bandwidth is virtually unlimited. Multimode fiber is used for voice, data, security, and video systems.

StandardYearBandwidthData Rate b199920MHz11Mb/s a199920MHz54Mb/s g200320MHz54Mb/s n200920MHz, 40MHz 600Mb/s

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