Chapter 2: Ports and Connectors
Contents
1. FIGURE 2 19 USB B type port and connector You can also find USB extenders These have a USB A port on one end anda USB A connector on the other You can use these for extending a mouse or key board cable and for connecting wide USB devices such as thumb drives to portable computers Many current devices such as keyboards mice joysticks microphones scan ners printers modems PDAs digital cameras lap warmers cup heaters per sonal fans lamps and more connect to the PC via USB FO gt FIGURE 2 20 Mini USB port and connector CHAPTER2 Ports and Connectors 3 Travel Assistance wns For more information about USB visit http www usb org USB devices are hot swappable which means that you can connect or discon nect them at any time without powering down your PC USB technology en ables you to connect up to 127 devices together in a series called a daisy chain Travel Advisory For the purposes of the CompTIA A Certification exams you need to know that you can connect 127 devices together but for real life on the job Situations it s a bad idea to hit this maximum Some applications reserve bandwidth and you could wind up with quite a mess Too much of a good thing isn t good IEEE 1394 IEEE 1394 is an exciting communications technology created in a joint effort by Apple Computers Texas Instruments and the IEEE organization The IEEE 1394 standard has been widely adop2. but many other devices have used paral lel ports such as external CD ROM drives Zip drives and scanners Exam Tip Parallel communications transfer data 8 bits or 1 byte at a time Printers that connect to parallel ports on the PC have a centronics port rather than a parallel port Centronics connectors have a central tongue with contacts rather than pins Figure 2 3 and come in two varieties The more common is the 36 pin IEEE 1284B connector the rarely used variety is the mini centronics IEEE 1284C connector Figure 2 4 FIGURE 2 3 IEEE 1284B centronics connector and port CHAPTER2 Ports and Connectors 20 E SN FIGURE 2 4 IEEE 1284C mini centronics connector Local Lingo IEEE IEEE stands for the Institute of Electrical and Electronics Engineers the international organization that creates standards for electrical things such as ports cables and connectors You ll see them again later in this chapter Parallel ports traditionally get I O address 378 and IRQ 7 LPT1 but as with the serial port assignments modern motherboards give you the option of changing this setting Technological advances such as the Extended Capability Port ECP and the Enhanced Parallel Port EPP offer improved throughput to about 10 times faster than a standard parallel port Standard Single Function Ports Objective 2 02 E PC sports several single function ports for connecting peripherals such as k
3. BNC connectors called component and RGB video respectively Figure 2 9 shows both types of ports on monitors CHAPTER2 Ports and Connectors 29 Components FIGURE 2 9 RGB and component connectors Audio Ports At one time audio was considered an extra add on but sound is standard issue on modern PCs Most audio ports take the form of the popular 1 8 mini audio connectors commonly seen on the Sony Walkman or other similar gadgets A PC typically has at least three color coded sound ports a green speaker output port a pink microphone input port and a blue auxiliary input port as shown in Figure 2 10 Better audio systems offer more jacks for rear speakers center speaker and subwoofer Travel Advisory some sound cards have audio ports that are all one color If you run into one of those you can try to figure out what the obscure symbols mean or get the information from a user manual or the manufacturer s Web site FIGURE 2 10 Sound card 1 8 mini audio connectors 30 MIKE MEYERS A CERTIFICATION PASSPORT You will occasionally see variations particularly on systems with high performance sound cards Some have separate outputs for each audio channel or they may incorporate one or two special connectors called Sony Philips Digi tal Interface S PDIF ports as shown in Figure 2 11 S PDIF ports come in two flavors electrical and optical The electrical port uses an RCA connector on a coaxial cable t
4. call them NICs even when the network adapter is built into a motherboard and thus distinctly lacking in card ness FIGURE 2 16 An RJ 45 connector and port J MIKE MEYERS A CERTIFICATION PASSPORT FIGURE 2 17 SC ST and LC LC fiber connectors Make sure you know the difference between RJ 11 connectors and RJ 45 connectors and that you can easily tell the difference between the two at a glance Modern Multifunction Objective 2 03 Ports Mas PCs use one or more multifunction ports to supplement or replace the aged serial and parallel ports All newer machines have universal serial bus USB ports many have IEEE 1394 FireWire ports and a few have a small computer systems interface SCSI port All three come in at least two varieties and can be used to connect everything from printers to digital cameras USB USB comes in two flavors USB and Hi Speed USB Regular USB often mis takenly called USB 1 1 devices transfer data at speeds of 1 5 or 12 megabits per second Mbps making them much faster than parallel or serial communica tions Hi Speed USB is faster still capable of bursts up to 480 Mbps Note that despite the huge difference in speeds Hi Speed USB technology is fully back ward compatible with regular USB devices You can plug a regular USB device into a Hi Speed port in other words and it will work CHAPTER2 Ports and Connectors 39 Local Lingo USB 1 1 All current USB devi
5. won t work Mice go into mouse ports keyboards go into key board ports Some portable computers have a single black or gray mini DIN port that can handle both a mouse and a keyboard though obviously not at the same time Video Ports Standard cathode ray tube CRT monitors and many projectors connect to your PC using a 15 pin D subminiature connector arranged in three rows of five pins each The corresponding video port on the PC as shown in Figure 2 7 ac commodates only that connector No other port on your PC looks like this one Many flat panel liquid crystal display LCD monitors and some projectors use a specially keyed 24 pin Digital Visual Interface DVI connector that plugs into a DVI port on the back of your video adapter card as shown in Figure 2 8 DVI comes in several varieties such as analog DVI A and digital DVI D Chapter 10 covers monitors and projectors in more detail RE AAPA ow ot Pe SP Re Bane ji eat Oe A D Dew AVER FIGURE 2 7 A female 15 pin DB connector 27 28 MIKE MEYERS A CERTIFICATION PASSPORT Sd am OF ag Oe lt fs S m E TE H a jE i amp 6 amp SE FIGURE 2 8 DVI connector for a flat panel monitor Local Lingo Thin film transistor The most common LCD monitors use a technolo gy called thin film transistor TFT Many techs erroneously refer to all LCD monitors as TFTs Some video cards connect to display devices using three RCA connectors or five
6. Ports and Connectors ITINERARY o Objective 2 01 Legacy Multifunction Ports o Objective 2 02 Standard Single Function Ports o Objective 2 03 Modern Multifunction Ports NEWBIE SOME EXPERIENCE EXPERT 2 5 hours 1 5 hours 1 hour 21 22 MIKE MEYERS A CERTIFICATION PASSPORT Mastering the craft of the PC technician requires that you learn a lot of details about what sometimes seems to be thousands of individual parts connections and settings Even the most basic PC contains many hardware components each with its own set of characteristics shapes sizes and colors Fortunately it s much simpler than it seems Computer makers use only a few types of connec tors for most devices so once you learn one type of connector you ll know how to use it on any type of PC This chapter describes integrated I O devices the major connectors plugs and sockets that you ll find on a typical PC and spells out many of the amazing array of acronyms and abbreviations used by techs The CompTIA A certifica tion exams expect you to recognize a particular part simply by seeing what type of connector attaches to that part so pay attention folks Legacy Multifunction Ports Objective 2 01 5 techs don t go around saying Just plug that doohickey into the what chamacallit on the back of the PC and you shouldn t either These things have names after all so you should get into the habit of using them Every ca ble has a c
7. ave a Type B port 10 E The IEEE 1394a FireWire standard enables data transfers of up to 400 megabits per second 11 You can daisy chain up to 63 devices on a single FireWire port
8. ces fall into the USB 2 0 specification The initial specification that came to market was called USB 7 7 and matched the data throughput and connections of the current USB 2 0 not Hi Speed devices Many techs and consumers continue to use the term USB 1 1 to describe the lower speed USB 2 0 devices Some marketing materials distinguish between 1 5 and 12 Mbps USB devices as USB and Full Speed USB although the latter term is not used in the specification at all The CompTIA A certification exams use the term USB 1 1 to USB ports come in three varieties A B and mini All are female and rectangu lar shaped The four contact pins are mounted on a plastic protrusion that keeps you from inserting the USB cable improperly You plug the flat USB A connector into the corresponding port on a PC or USB hub a generic term for a device with multiple USB ports Figure 2 18 Most bigger peripherals such as printers and scanners have a B port into which youd plug a B connector Figure 2 19 Small USB devices such as digital cameras and music players use the mini port Figure 2 20 shows a mini USB port and connector r Ra fe J do O ETE gil f i Ye i a F ia DA gt A N Tiir ti a MA A o gt ra a3 Ag gt i a we Nal pial CA 1 Cia pi PAI N N ai a N By FIGURE 2 18 USB A type port and connector 36 MIKE MEYERS A CERTIFICATION PASSPORT
9. ed certain system resources and serial ports are no exception The CPU uses input output I O addresses to give commands to devices some devices use an interrupt request IRQ to contact the CPU Most motherboards have at least one serial port appropriately called Serial Port 1 By default this port gets assigned the I O address 3F8 and IRQ 4 COM1 The rare Serial Port 2 ona PC gets I O address 2F8 and IRQ 3 COM2 by default You can use the CMOS setup utility to change the resources assigned to de vices built into the motherboard such as serial ports Further you can enable or disable the serial port s in the CMOS setup utility to free up resources although you d need to do this only on old computers Chapter 7 covers the CMOS setup utility in great detail Local Lingo System setup utility Many techs refer to the CMOS program as the system setup utility The latter term happens to be more accurate as no modern PC uses a complementary metal oxide semiconductor chip to store CMOS information but the older term has stuck As one old tech said looking me straight in the eye CMOS is CMOS son Parallel Ports Parallel ports are the 25 pin 13 on the top row 12 on the bottom female ports on the back of older PCs as shown in Figure 2 2 Folks often incorrectly refer to 24 MIKE MEYERS A CERTIFICATION PASSPORT FIGURE 2 2 A 25 pin parallel port parallel ports simply as printer ports
10. een the port and device is powered down The 6 pin standard FireWire 400 ports are slightly taller than USB ports and rounded on one end The connector plugs are of course shaped to fit as shown in Figure 2 21 Some devices such as digital camcorders use a 4 pin mini FireWire connector similar to the mini USB connector although they are certainly not interchangeable Figure 2 22 FireWire 800 devices use a square 9 pin connector Figure 2 23 You can get adapters and two headed cables to connect a FireWire 400 device into a FireWire 800 port i f I i 4 f i FireWire 400 IEEE 1394a connector and port CHAPTER2 Ports and Connectors 39 For more information regarding FireWire and the IEEE 1394 standard visit http www ieee org FIGURE 2 23 FireWire 800 IEEE 1394b port and connector 40 MIKE MEYERS A CERTIFICATION PASSPORT SCSI SCSI amusingly pronounced skuzzy has been around for a long time In novations in SCSI technology have kept SCSI competitive with other enhanced technologies such as USB and FireWire Many high end PCs have built in SCSI connectors and SCSI controller cards are widely available to add SCSI ports to your system SCSI devices have a variety of interfaces SCSI 1 SCSI 2 Ultra SCSI Wide Ultra SCSI just to name a few but the 68 pin female Ultra 320 port shown in Figure 2 24 is the most common today You may also see 50 pin or 25 pin ports on some older dev
11. es and daisy chain up to 127 devices in one PC The Type A connector goes into the USB port the Type B or mini connector goes into the USB device USB a k a normal USB 1 1 is capable of throughput speeds up to 12 Mbps while Hi Speed USB is good for up to 480 Mbps IEEE 1394 is also known as FireWire iLink and Lynx The 1394a version is capa ble of speeds up to 400 Mbps and 1394b runs at up to 800 Mbps Either version of IEEE 1394 enables you to connect up to 63 devices to a single IEEE 1394 port Finally the 68 pin ports used by Ultra 320 devices are the most common ones seen on the many SCSI technologies available today but you might also see 50 pin 25 pin or other varieties REVIEW QUESTIONS 1 Which of these connectors can you use to connect a keyboard to a PC Select two Mini DIN 9 pin serial 25 pin parallel USB 9 oO WP 42 MIKE MEYERS A CERTIFICATION PASSPORT 2 Which of these connectors can you use to connect a CRT monitor to a PC A 25 pin serial B 9 pin serial C 15 pin D sub in two rows D 15 pin D sub in three rows 3 Which of the following ports can be found on network cards A HDMI B Parallel C RJ 45 D USB 4 How many pins does a parallel port have A 10 B 25 C 34 D 36 5 How is data transferred in serial communications A 10 bits at a time B 1 bit at atime C 1 byte at atime D 16 bits at atime 6 How is data transferred in parallel communications Select two A 8 bit
12. eyboards monitors and the like With only a couple of exceptions these standard ports support only a single type of device The Keyboard Port Keyboards come in a variety of styles from the plain Jane rectangular type writer substitute to the exotically curved multifunction gadget that s bristling 26 MIKE MEYERS A CERTIFICATION PASSPORT with special function hotkeys and equipped with ports of its own Regardless of their appearance however all keyboards enable you to do one thing enter commands into your PC Modern PCs have a purple 6 pin mini DIN commonly called a PS 2 connec tor port Figure 2 5 The mini DIN port is keyed so you can insert the key board connector only one way The Mouse Port Like keyboards mice come in an array of sizes and shapes and they use a variety of connectors to attach to the PC see Figure 2 6 All mice enable you to manip ulate the operating system OS and applications Traditionally mice plugged into one of the serial ports on the back of the PC but most motherboards today have a dedicated mini DIN mouse port Aside from color the green mouse port appears identical to the purple PS 2 keyboard port but they re not interchangeable FIGURE 2 5 A 6 pin mini DIN connector CHAPTER 2 Ports and Connectors FIGURE 2 6 A serial mouse connector left and a PS 2 mouse connector You can plug a PS 2 mouse connector into a PS 2 keyboard port and vice versa but they
13. he optical uses a fiber connector Some sound cards from Cre ative Labs use a 1 8 mini audio jack for electrical S PDIF Multimedia Ports The convergence of television music and the computer has many newer PCs sporting various multimedia connectors Some of these connectors such as the RG 6 coaxial connector have been around for a long time The RG 6 con nector sits on the video card or a dedicated TV tuner card and enables your PC to receive video and audio signals from a cable company or video cassette player Other older connectors include S Video for sending video content from the PC to the TV and composite connectors for connecting left and right channel audio and a single video source into or out from the PC Figure 2 12 shows an ATI All in Wonder card with the many multimedia connectors it offers The latest media center PCs designed to fit into your living room d cor rather than on your desk come with High Definition Multimedia Interface SPDIF IN S PDIF connectors electrical left and optical right CHAPTER2 Ports and Connectors 31 FIGURE 2 12 Multimedia card HDMI ports Figure 2 13 for connecting the PC to a high definition televi sion HDTV The HDMI interface handles both the high definition video sig nal and multichannel digital audio streams FIGURE 2 13 HDMI connector 32 MIKE MEYERS A CERTIFICATION PASSPORT MIDI Joystick Ports Older PCs have an integrated female DB 15 po
14. ices or PCs Note that the very fine port sockets shown in the picture are matched to fine contact pins on the male Ultra 320 connector Take it from me these tiny pins bend and break easily so handle with care Data throughput on SCSI varies from around 5 to 80 megabytes per second MBps for early incarnations to 320 MBps for many current versions Chapter 8 covers the amazing variety of SCSI devices and standards Travel Assistance For more information on SCSI check out the SCS Trade Organization at http www scsita org FIGURE 2 24 Ultra 320 port CHAPTER 2 Ports and Connectors 4 CHECKPOINT W Objective 2 01 Legacy Multifunction Ports The 9 pin and 25 pin serial ports and the 25 pin parallel ports are used for connecting serial and parallel devices respectively to the PC Serial devices transfer data 1 bit a time whereas parallel devices transfer data 8 bits at a time W Objective 2 02 Standard Single Function Ports Keyboards connect to the motherboard with 6 pin mini DIN PS 2 or USB connectors Mice connect to the 9 pin serial bus in older systems and PS 2 or USB in newer systems Make sure you remember the 15 pin three row D sub port is for video whereas the 15 pin two row D sub port is for MIDI devices or joy sticks Finally know the difference between the RJ 11 connectors for mo dems and the RJ 45 connectors for NICs W Objective 2 03 Modern Multifunction Ports USB enables you to hot swap devic
15. onnector at the end that plugs into a corresponding port on a PC Connectors carry data and sometimes power between devices attached to the PC Ports are the interfaces the doorways used to connect devices to the PC Connectors and ports can be either male or female defined as having pins or sockets respectively Let s start with the two ancient multifunction ports that linger on most mod ern PCs serial ports and parallel ports Serial and parallel ports have a slight D shape which allows only one proper way to insert a plug into the socket and makes it easier to remember what they re called Technically they re known as D sub or D subminiature connectors but most techs call them DB Serial Ports Serial ports come in 9 pin and 25 pin varieties Figure 2 1 Of the two the 9 pin five pins on the top row four on the bottom variety is much more com mon although even those are rapidly disappearing from modern PCs Serial ports transfer data 1 bit the smallest unit of data in the PC world at a time with a maximum throughput speed of 115 kilobits per second Kbps CHAPTER2 Ports and Connectors 23 FIGURE 2 1 A 25 pin serial port and a 9 pin serial port Devices that connected to the PC via the serial port included mice external mo dems label printers personal digital assistants PDAs and digital cameras Exam Tip Make sure you know that serial ports transfer data 1 bit at a time All devices in a PC get assign
16. rt for connecting joysticks or other game controllers These ports also support MIDI devices such as a music synthesizer keyboard although you need a special breakout box to make the MIDI connection Unlike DB 15 video connectors MIDI Joystick connectors have pins arrayed in two rows with eight on the top and seven on the bottom as shown in Figure 2 14 Make sure you know that the two row 15 pin DB connector can be used for both MIDI devices and joysticks Modem Ports PC modem ports look identical to female telephone jacks and use standard two wire RJ 11 telephone cables and connectors Figure 2 15 The locking clips on the male RJ 11 connectors secure the cable into the port Most modems also have an output port for a telephone FIGURE 2 14 MIDI Joystick port CHAPTER2 Ports and Connectors 30 FIGURE 2 15 RJ 11 ports on a modem Network Interface Ports Network interfaces come in two main varieties Most network interface cards NICs and motherboards have an eight wire RJ 45 port Figure 2 16 RJ 45 connectors look like wider than normal RJ 11 telephone connectors and plug into the female RJ 45 ports in the same manner that RJ 11 telephone cables plug into a modem High end NICs have two fiber connections in out of one vari ety or another The most common fiber connectors are the SC ST and the LC LC Figure 2 17 Local Lingo NIC Network interface cards NICs enable PCs to connect to a network Techs
17. s at a time B 1 byte at atime C 1 bit ata time D 8 bytes at a time 7 In theory how many USB devices can you daisy chain together A 1 B 2 C 63 D 127 CHAPTER2 Ports and Connectors 43 8 Which connector provides high quality video and audio 10 11 A HDMI B S PDIF C S Video D VGA To what does a Type A USB connector connect A To a USB port on the PC B Toa USB device C Toa serial port on the back of your PC D Toa USB modem What is the top data transfer speed possible under the IEEE 1394a standard A 50 megabits per second B 400 megabits per second C 400 megabytes per second D 800 megabits per second How many devices can you daisy chain on a single FireWire connection A 63 B 65 C 127 D 1023 REVIEW ANSWERS 1 2 3 4 5 6 7 EXD Keyboards can use a mini DIN or USB connector D An CRT monitor cable has a 15 pin D sub connector in three rows Most network cards have RJ 45 ports E Parallel ports have 25 pins or contacts Serial communications transfer data 1 bit at a time AE Parallel communications transfer data 8 bits 1 byte at a time D You can in theory daisy chain 127 USB devices together 44 MIKE MEYERS A CERTIFICATION PASSPORT 8 The HDMI connector can handle high definition video and multiple digital audio signals 9 L The Type A connector on a USB cable connects to the USB ports on the back of your PC USB devices h
18. ted not only by computer and peripheral makers but also by manufacturers of home electronics such as digital video recorders Different manufacturers market IEEE 1394 technology under different trade names such as FireWire Apple iLink Sony or Lynx Texas Instruments but they all refer to the same thing Of these terms FireWire is the most popular term among techs Local Lingo FireWire iLink and Lynx The terms FireWire iLink and Lynx all refer to the IEEE 1394 interface 30 MIKE MEYERS A CERTIFICATION PASSPORT The original specification for FireWire 1394a calls for data transfers of up to 400 Mbps The current generation of FireWire 1394b is capable of speeds up to a blinding 800 Mbps What s even more impressive is that the de sign spec for FireWire states that speeds of up to 1600 Mbps are possible FireWire technology is a very good match for video external hard drives backup storage devices and other hardware that needs real time data access Connecting FireWire devices together enables them to communicate Running a FireWire cable between two PCs for example creates an instant point to point network for sharing files You can connect up to 63 FireWire devices to gether in a daisy chain although you would need devices that came with their own power supply to use that many One cool feature of FireWire chains is that you can use a device somewhere down the chain even if one or more devices in betw
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