What is I/O Ports & it's types

The word “port” is used often in the computer industry, and has many different meanings depending on what technology is being referred to. In this section, we detail input/output (I/O) ports. I/O ports allow for connections to hardware. This hardware could be internal or external. The ports are associated with copper circuits and memory ranges that allow the communication of data between the CPU, RAM, and the ports themselves.

I/O ports refer to input/output ports. These are connectors on your computer that enable you to connect to digital cameras, video cameras, televisions, external storage devices, printers and scanners.

VGA Port

Connect a PC to a monitor. This is a venerable but now completely standard monitor interface. The original VGA monitors could do no more than 640x480. During the mid 1990's, more advanced monitors were called "SVGA" (for Super). Since all monitors can display more than 640x480 today, the two terms are now interchangeable.

15 Pins

VGA Port Pins Configuration

COM Ports or Serial Ports

Connect a PC to an external modem, serial mouse, etc. DOS calls these ports COM1-COM4. The small version is slightly more popular than the large version. Dating from the PC XT, these are ubiquitous but rarely used.

9 Pins

Serial Port 9 Pins Configuration

Parallel Port

Connect a PC to a printer. DOS calls this port LPT1. Another PC XT holdover, this port is virtually always used to connect to a printer.

25 Pins

Parallel Pins Configuration

Game Port

Connect a PC to a joystick (or two). This port is now mostly replaced by USB.
This DB-15 connector has several (extremely primitive) analog inputs and a small number of digital inputs and outputs. 

15 Pins

Game Pins Configuration

PS/2 Port

Connect a PC to its keyboard and mouse. Though both ports look identical, the mouse (green) and keyboard (purple) ports are not interchangeable.  Usually both ports are color coded or labeled.

6 Pins

Game Port Pins Configuration

Pin	Assignment	Pin	Assignment
1	Keyboard Data	1	Mouse Data
2	(Reserved)	2	(Reserved)
3	Ground	3	Ground
4	Keyboard Power (+5V)	4	Mouse Power (+5V)
5	Keyboard Clock	5	Mouse Clock
6	(Reserved)	6	(Reserved)

AT Keyboard Port

Connect a PC to an older keyboard. If you don't plug in a keyboard here, you get the famous BIOS boot error:

5 Pins

AT Keyboard Port Pins  Configuration

IDE Port

 IDE stands for Integrated Device Electronics. An IDE interface is a way of connecting a device, typically storage, to a computer system. The IDE interface was originally used to integrate hard disk drives to a computer system. Over time a number of other devices have come to use the IDE interface including CD-Rom drives, tape drives, zip drives, etc.

There are two types of IDE port (Primary & Secondary).

IDE Drive Master or IDE Drive 0 or IDE Drive 1

IDE Drive Slave or IDE Drive 1 or IDE Drive 2

40 Pins

IDE Port Pins  Configuration

Pin	Name	Dir	Description
1	/RESET		Reset
2	GND		Ground
3	DD7		Data 7
4	DD8		Data 8
5	DD6		Data 6
6	DD9		Data 9
7	DD5		Data 5
8	DD10		Data 10
9	DD4		Data 4
10	DD11		Data 11
11	DD3		Data 3
12	DD12		Data 12
13	DD2		Data 2
14	DD13		Data 13
15	DD1		Data 1
16	DD14		Data 14
17	DD0		Data 0
18	DD15		Data 15
19	GND		Ground
20	KEY	-	Key (Pin missing)
21	DMARQ	?	DMA Request
22	GND		Ground
23	/DIOW		Write Strobe
24	GND		Ground
25	/DIOR		Read Strobe
26	GND		Ground
27	IORDY		I/O Ready
28	SPSYNC:CSEL	?	Spindle Sync or Cable Select
29	/DMACK	?	DMA Acknowledge
30	GND		Ground
31	INTRQ		Interrupt Request
32	/IOCS16	?	IO ChipSelect 16
33	DA1		Address 1
34	PDIAG	?	Passed Diagnostics. Used for 80-pin cable detect.
35	DA0		Address 0
36	DA2		Address 2
37	/IDE_CS0		(1F0-1F7)
38	/IDE_CS1		(3F6-3F7)
39	/ACTIVE		Led driver
40	GND		Ground

FDC Port

Connect a PC to a Floppy Disk Drive.

FDC or Floppy

34 Pins

                                                        IDE Port Pins  Configuration

Pin	Name	Dir	Description
2	/REDWC		Density Select
4	n/c		Reserved
6	n/c		Reserved
8	/INDEX		Index
10	/MOTEA		Motor Enable A
12	/DRVSB		Drive Sel B
14	/DRVSA		Drive Sel A
16	/MOTEB		Motor Enable B
18	/DIR		Direction
20	/STEP		Step
22	/WDATE		Write Data
24	/WGATE		Floppy Write Enable
26	/TRK00		Track 0
28	/WPT		Write Protect
30	/RDATA		Read Data
32	/SIDE1		Head Select
34	/DSKCHG		Disk Change/Read

SATA Port

SATA Stand for Serial Advanced Technology Attachment.

Connect a PC to a Hard Drive & CD-Rom.

7 Pins

                                                        SATA Port Pins  Configuration

Pin	Name	Function
1	GND	Ground
2	A+	Transmit+
3	A-	Transmit-
4	GND	Ground
5	B-	Receive-
6	B+	Receive+
7	GND	Ground

DVI Port

DVI was developed by the Digital Display Working Group (DDWG). This interface provides a high-speed connection for visual data that is displayed technology independent. DVI interface primarily focused at providing a connection between computer and display devices. (Monitor, LCD & Projector)

24 Pins

                                                       DVI Port Pins  Configuration

Pin	Signal
1	T.M.D.S DATA 2-
2	T.M.D.S DATA 2+
3	T.M.D.S DATA 2/4 SHIELD
4	T.M.D.S DATA 4-
5	T.M.D.S DATA 4+
6	DDC CLOCK
7	DDC DATA
8	ANALOG VERT. SYNC
9	T.M.D.S DATA 1-
10	T.M.D.S DATA 1+
11	T.M.D.S DATA 1/3 SHIELD
12	T.M.D.S DATA 3-
13	T.M.D.S DATA 3+
14	+5V POWER
15	GND
16	HOT PLUG DETECT
17	T.M.D.S DATA 0-
18	T.M.D.S DATA 0+
19	T.M.D.S DATA 0/5 SHIELD
20	T.M.D.S DATA 5-
21	T.M.D.S DATA 5+
22	T.M.D.S CLOCK SHIELD
23	T.M.D.S CLOCK+
24	T.M.D.S CLOCK-
C1	ANALOG RED
C2	ANALOG GREEN
C3	ANALOG BLUE
C4	ANALOG HORZ SYNC
C5	ANALOG GROUND

DDC = Display Data Channel. T.M.D.S = Transition Minimized Differential Signal.

USB Port

USB (Universal Serial Bus) designed to connect peripherals such as mice, keyboards, saneers, digital cameras, printers, hard disk, & networking  etc. components to PC.

                                                                               

                                                       USB Port Pins  Configuration

Pin	Name	Cable color	Description
1	VCC	Red	+5 VDC
2	D-	White	Data -
3	D+	Green	Data +
4	GND	Black	Ground