PC Hardware

Tutorial Summary: Printers Modems and Cables

The following points summarize the key concepts in this tutorial:


  • The three most commonly encountered types of printers are dot-matrix, ink-jet, and laser printers.
  • As a computer technician, you can expect to encounter printing problems on a regular basis.
  • Most printer problems can be resolved quickly by checking for paper jams, expended consumables, or improper use.
  • The key components of a laser printer are its power supply, photosensitive drum, eraser lamp, primary corona, laser, transfer corona, and fuser.


  • Modems convert parallel digital data to and from serial analog data.
  • Modem speeds are based on bps (bits per second).
  • CCITT (now ITU-T) establishes standards for modem communication.
  • AT commands are used to manually communicate with and test a modem.
  • Modems can be installed internally or externally.
  • The primary modem problem is IRQ conflicts.

Cables and Connectors

  • There are many different types of computer cables and connectors. It is important for the computer technician to be able to identify each of them.
  • Distinguishing between a male or a female connector is often the key to identifying the connector's function.
  • Loose or poorly connected cables are often the cause of computer problems.


  1. Name three types of printers and describe their advantages and disadvantages.
  2. The dot-matrix printer is an ____________ printer. Name at least one advantage of this type of printer. Name at least one disadvantage.
  3. What are the six steps of laser printing?
  4. Which components are usually included in a laser printer's replaceable toner cartridge? Why?
  5. What causes black spots to appear on a document that has been printed on a laser printer? How can this problem be resolved?
  6. What is the IEEE 1284 standard?
  7. What kinds of signals do telephones use? What kinds of signals do computers use?
  8. What is the purpose of a modem?
  9. Which AT command is used to take the phone off the hook?
  10. What is the difference between baud and bps?
  11. What is the name of the chip that converts data from parallel to serial?
  12. Name three transfer protocols.
  13. What is Zmodem? What are its advantages over other protocols?
  14. Define handshaking.
  15. What are AT commands and how can a computer technician use them?
  16. Explain the difference between half-duplex and full-duplex. What makes them different? Where or when is each used?
  17. What is the difference between synchronous and asynchronous communication?
  18. Why are fax standards different from modem standards?
  19. Describe a null-modem cable.
  20. In addition to the cost of the printer, what other costs should be considered when purchasing a printer?
  21. What does bps stand for?
  22. Identify as many cables and connectors as you can.
  23. What type of connector is used for a parallel port on the computer?
  24. What type of connector is used for a parallel port on the printer?