Serial and Parallel Ports

Introduction A port is a point at which an external device (peripheral) attaches to the computer system. Ports allow data to be sent/retrieved from the external device. Modern computers carry many types of ports For example, mouse , keyboard , serial, USB, game, parallel (printer), microphone, telephone, network etc.

A port is a point at which an external device (peripheral) attaches to the computer system. Ports allow data to be sent/retrieved from the external device.

Modern computers carry many types of ports For example, mouse , keyboard , serial, USB, game, parallel (printer), microphone, telephone, network etc.

Classification of Ports The most common type of ports are -: Serial port – 1bit is transmitted at a time; COM port is a type of serial port . Parallel port – Allows multiple bits (E.g. 8 or 16) bits to be transmitted simultaneously. Printers normally connected to this type of port.

The most common type of ports are -:

Serial port – 1bit is transmitted at a time; COM port is a type of serial port .

Parallel port – Allows multiple bits (E.g. 8 or 16) bits to be transmitted simultaneously. Printers normally connected to this type of port.

Serial Port A serial port is a serial communication physical interface through which information transfers in or out one bit at a time . Serial ports represent the first interfaces to allow computers to exchange information with the "outside world". The term serial refers to data sent via a single wire: the bits are sent one after the other

A serial port is a serial communication physical interface through which information transfers in or out one bit at a time .

Serial ports represent the first interfaces to allow computers to exchange information with the "outside world".

The term serial refers to data sent via a single wire: the bits are sent one after the other

Serial ports also called RS-232. (Recommended Standard) In serial ports, there will be two data lines: One transmission and one receive line. To send a data in serial port, it has to be sent one bit after another with some extra bits like start bit, stop bit and parity bit to detect errors. Serial connectors generally have 9 or 25 pins. Serial port uses a 9- pin connector (type DB-9) COM port is a type of serial port

Serial ports also called RS-232. (Recommended Standard)

In serial ports, there will be two data lines: One transmission and one receive line. To send a data in serial port, it has to be sent one bit after another with some extra bits like start bit, stop bit and parity bit to detect errors.

Serial connectors generally have 9 or 25 pins.

Serial port uses a 9- pin connector (type DB-9)

COM port is a type of serial port

Parallel Ports Parallel data transmission involves sending data simultaneously on several channels (wires). The parallel ports on personal computers can be used to send 8 bits (one octet) simultaneously via 8 wires. Parallel ports are easy to program and faster compared to the serial ports. But main disadvantage is it needs more number of transmission lines. Because of this reason parallel ports are not used in long distance communications.

Parallel data transmission involves sending data simultaneously on several channels (wires). The parallel ports on personal computers can be used to send 8 bits (one octet) simultaneously via 8 wires.

Parallel ports are easy to program and faster compared to the serial ports. But main disadvantage is it needs more number of transmission lines. Because of this reason parallel ports are not used in long distance communications.

Parallel ports, like serial ports, are built into the mother board. DB25 connectors allow connection to an exterior element (e.g. a printer).

Parallel ports, like serial ports, are built into the mother board. DB25 connectors allow connection to an exterior element (e.g. a printer).

Accessing Serial port using C# // This is a new namespace in .NET 2.0 // that contains the SerialPort classusing System.IO.Ports; private static void SendSampleData() { // Instantiate the communications // port with some basic settings SerialPort port = new SerialPort( "COM1", 9600, Parity.None, 8, StopBits.One); //Open the port for communications port.Open(); //Write a string port.Write("Hello World"); // Write a set of bytes port.Write(new byte[] {0x0A, 0xE2, 0xFF}, 0, 3); // Close the port port.Close(); }

// This is a new namespace in .NET 2.0

// that contains the SerialPort classusing System.IO.Ports;

private static void SendSampleData()

{

// Instantiate the communications

// port with some basic settings

SerialPort port = new SerialPort( "COM1", 9600, Parity.None, 8, StopBits.One);

//Open the port for communications

port.Open();

//Write a string port.Write("Hello World");

// Write a set of bytes

port.Write(new byte[] {0x0A, 0xE2, 0xFF}, 0, 3);

// Close the port

port.Close();

}

Conclusion A serial port is a general-purpose interface that can be used for almost any type of device , including modems , mice , and printers (although most printers are connected to a parallel port ).

A serial port is a general-purpose interface that can be used for almost any type of device , including modems , mice , and printers (although most printers are connected to a parallel port ).

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