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CHAPTER Modems

CHAPTER Modems. Chapter Objectives. Discuss basic modem related issues Standards, Hayes compatibility etc. Describe the different types of practical modems available Internal, external, null, short-haul modems etc. Present the profile of sample practical modems

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CHAPTER Modems

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  1. CHAPTER Modems

  2. Chapter Objectives • Discuss basic modem related issues • Standards, Hayes compatibility etc. • Describe the different types of practical modems available • Internal, external, null, short-haul modems etc. • Present the profile of sample practical modems • Asynchronous and synchronous modems • Show the establishment of a fiber-optic communication link using the fiber-optic interface

  3. Chapter Modules • Modem Functional Considerations • Internal, External and Portable Modems • A Modem Profile • Modem Software Installation • A Practical Asynchronous/Synchronous Modem • Faster Modem Standards • Fiber-optics Connection • Null Modem and Short-haul Modem • Cable Modem • DSL Modem

  4. END OF CHAPTER INTRODUCTION

  5. MODULE Modem Functional Considerations

  6. Module Objectives • List the two types of modem standards • Describe the features that are standardized in modem communication • Modulation, data compression etc. • Explain the relevance of standards to speed • Discuss Hayes compatibility • List a few common modem features

  7. Major Modem Standards • ITU standard • Universal standard • Currently in use • Bell standard • Earlier low speed modem standard • No more in use

  8. Standards in Modem Communication • Modulation standard • Data compression standard • Error correction Standard

  9. Speed and Modulation Standards • Each speed is associated with a modulation standard • V.34 is an example standard for the communication speed of 28,800 bps • Higher speed modems can operate at lower speeds as well • E.G 28,800 bps modem can communicate at 14,400 bps

  10. Data Compression Standards in Modem • MNP 5 • ITU V.42 bis

  11. Error Correction Standard • MNP 2-4

  12. Understanding Hayes Compatibility • IBM is to micros what Hayes is to modems • Hayes compatibility • Ensured by adherence to the Hayes command set known as the AT command set • Ensures wide availability of software

  13. Command Translation for PCs and Modems • Commands for the PC • Translated into machine language and executed • E.G. Identifying a file for transmission • Commands for the modem • Generated in Hayes AT command set form and transmitted to the modem for execution • E.G. Command instructing the modem to dial

  14. Command Translation Intel Machine Code Software Intel Micro Modem Hayes AT Command

  15. Modem Features • Auto-dial • Auto-answer • Reverse calling • All the above features are standard in today’s Modems

  16. END OF MODULE

  17. MODULE Internal, External and Portable Modems

  18. Overview of Internal and External Modems • Internal modem • Installed in the expansion slot • Usually cheaper • Occupies one expansion slot • External modem • Connects to the serial port of the computer • More expensive • Does not occupy an expansion slot • But, it does utilize one of the available communication ports

  19. Internal Modems Source: Black Box

  20. External Modems Source: Black Box

  21. External Modem Ports and Connection To Com2 Port To Phone Jack RJ 11 Connection

  22. Modems for the Notebooks or PC Card Modem • Credit card size • Connects to the PCMCIA slot • Currently, known as PC card slots • PC cards have undergone major refinements • Efficient in their operation • Support high-speed communication devices

  23. PC Card Modems Source: Black Box

  24. Multi-Purpose PC Cards Source: Black Box

  25. END OF MODULE

  26. MODULE A Modem Profile

  27. Module Objectives • Examine the profile of an actual commercial modem • Discuss the standards as they relate to speed, data compression and error correction • Describe the FAX related communication details of the modem

  28. Profile of a Modem : Black Box Modem 288 Standards • Standards • ITU V.92, ITU V.90, ITU V.34, v.32bis, v.23, v.22bis, v.22, v.21, Bell 101 and Bell 212a • Protocols • Asynchronous and synchronous • Speed • V.90 ------ 56Kbps • V.34 -------> 28.8 Kbps • Others up to 14.4 Kbps • Possible up to 115.2 Kbps

  29. Profile: Operation, Interface and Connectors • Operation • 2 wire dial-up • Interface • RS-232C • Connectors • 1 DB25 female • 2 RJ11 female

  30. Profile: Speed and Compression Standards • V.90 • Supports 56 Kbps • V.34 • Supports 28.8 Kbps • V.32 • Supports 14.4 Kbps • V.42bis • Data compression standards • Up to 4 to 1 compression is possible

  31. Profile: Error Correction and Other Data Compression Standards • MNP 2-4 and 10 • Error correction • MNP 5 • Data compression

  32. Combined Effect of Speed and Compression Standards • Combined effect of v.34 and v.42bis data compression • 115.2 Kbps • This is only a theoretical reality • Practical speeds can be considerably slow

  33. Effect of Compression on File Transfer • Highest transfer speeds cannot be achieved in the case of already compressed files • Example: jpg, mp3 etc. • Because the above files are already compressed

  34. Profile: Fax Communication • Fax details • 14.4 Kbps speed • Class 1 and 2 fax software support • Works with class 3 fax machines

  35. END OF MODULE

  36. MODULE Modem Software Installation

  37. Module Objectives • Demonstrate the step-by-step installation of a modem in the Windows 95 operating system

  38. Installation Overview • The task is to install a Hayes Accura 28.8 modem on Com2 port • Overview of the Steps • Open the control panel • Choose the Modem icon • Proceed with the installation as instructed and finally specify the properties of the installed modem

  39. Demonstration of Modem Software Installation

  40. Accessing Modem Installation Icon Through Control Panel Start Settings Modems Control Panel

  41. Modem Icon in Control Panel Double Click

  42. Select the Modem

  43. Selecting the Modem Load the driver from the disk If the modem is not found in the List.

  44. Non-Mainstream Modem • If the modem is not of a popular type, then the driver must be loaded from a location on the disk • In the above case, select the option that says “Have Disk”

  45. Selecting the Port

  46. Finishing the Installation

  47. Installed Modem 1 2 3

  48. Modem General PropertiesIncrease the speed to the maximum. 1 2 3

  49. Connection Properties 1 2 3 4

  50. Port Settings 1 2

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