Table of Contents
What is a Serial Port?
An asynchronous port known as a serial port on a computer connects a serial device to the computer and enables bit-by-bit data transmission and reception. One of the earliest interface types is a connection type found in PCs. It was once used to connect printers and external modems,. But nowadays it is mostly used to connect peripherals like mice and game controllers to computers. An example would be connecting a modem to communication port 1 and a mouse to communication port 2. Modern serial ports are typically found on IBM-compatible computers as COM (communications) ports. And are used in scientific instruments and industrial machinery systems. An illustration of a cable with a DB9 serial connector.
Its data transfer rate is lower than that of a parallel port,. And it is occasionally referred to as an RS-232 port or COM port. DB25 and DB9 are the two different types of serial ports,. Where DB25 is a 25-pin connection and DB9 is a 9-pin connection. A parallel port is a female port that can send multiple bits at once,. In contrast to a serial port that can only send one bit at a time.
In the more recent computer, USB ports, which are faster and more versatile, have taken the place of serial ports. The configurations of system resources are denoted by COM1, COM2, COM3, and more; each COM position identifies an IRQ address as well as an input/output (I/O). Data terminal equipment and data terminal equipment,. Which are both commonly referred to as DTE and DCE, are used to transmit serial communication between devices using the RS-232 serial port standard. Since many of the connectors were large and inefficiently used, the standard made use of 25 pins, and the DE-9 connector gained popularity.
Serial communication required faster communication, such as external data storage units. The FireWire and the Universal Serial Bus (USB) introduced the faster interfaces. Using this new daisy chain technology, it might be possible to transfer large amounts of data quickly over a single bus. The use of a serial port is even less common today. Although it’s infrequently used, it serves as a communication device in flat-screen monitors, LCD displays, GPS receivers, LED displays, and bar-code scanners.
Identifying a serial port
The DB9 serial port, which is clearly visible in the image above, can be seen. The connection has nine pins and a male connector in the shape of the letter D.
Uses of serial port
Numerous hardware parts are listed below; you can buy them and use them with a serial port.
- Modem: The device that connects a computer. Or router to a broadband network is a modem, also referred to as a broadband modem. Its use is more widespread because it is so simple to use. However, it is most frequently applied to older machines. These modems include, for instance, DSL and cable modems.
- Mouse: A computer mouse, along with specialty mice, is a portable hardware input device that is one of the most frequently used devices for serial ports on computers without PS/2 or USB connections. The main function of a mouse is to open or execute a program, select an item, drag-and-drop files, folders, or other objects, hover, scroll, and perform other functions.
- Network: The creation of a network—a group of devices connected to one another and allowing data sharing—was one of the serial port’s original uses. A network that connects millions of people and enables information sharing among them is the internet. Bridges, Firewalls, Repeaters, Webcams, Switches, Hubs, Modems, and Routers are a few examples of network hardware.
- Printer: However, with older printers and plotters, the printer is an external hardware output device that is used to produce hard copies or soft copies but is not a commonly used device for serial ports today. It was used more frequently.
Serial port pin information
The DB9 connector’s pins are listed below along with information about each one’s function and signal name. With different computers, the serial port is designated as “10101”; these numbers are written in binary (zeros and ones). The user may also interpret the number “1” as the letter “I,” and the zeros as the letter “O,” creating what is sometimes referred to as the “IOIOI” port.
|1||DCD||Data Carrier Detec|
|4||DTR||Data Terminal Ready|
|6||DSR||Data Set Ready|
|7||RTS||Request To Send|
|8||CTS||Clear To Send|
Serial Ports are Outdated
Serial ports were phased out in the early 2000s as wireless and USB connections gained popularity. USB was less complicated, simpler to use, and much faster than serial. The older serial ports, which are required by input or other peripheral devices, can be hard to find in modern computer systems.
Standards for Serial Ports
Historically, the RS-232 has been the widely used standard for communications using serial ports. These serial ports and cables were used for the same purpose by PC keyboards and other computer peripherals. For RS-232 PCs, serial ports and cables typically have 9-pin DE-9 connectors. On specialized hardware, however, 25-pin DB-25 and other variations are available. Another common RS-422 component is found in many Macintosh computers. The RS-422 and RS-232 are no longer supported in favor of USB or FireWire communication.
How Serial Ports Work
A serial device is connected to a computer using the serial port,. Which has been a standard component of most computers for more than 20 years. And is considered the most basic external connection to a computer. Although most modern computers still connect to printers, PDAs, and digital cameras via the serial port,. Many more recent systems are starting to replace the serial port. Additionally, some computers have more than two serial ports available.
The word “serial” derives from the fact that the serial port serializes data by sending each of the 8 bits in a byte one at a time. The benefit is that it only needs one wire to transmit the eight bits. If it has 8 wires, it also has the drawback of sending data 8 times slower. Additionally, serial ports reduce the size and cost of cables while also making them smaller. A serial port sends a start bit, which is a single bit with the value 0, before each byte of data. Each byte of data is followed by a stop bit that signals the end of the byte.
Each device can transmit and receive data through a serial port in a bidirectional manner. It is also referred to as COM ports for communication. If both devices share the same pins, communication would only be possible in half-duplex and could only move information in one direction at a time. Because using different pins makes communication full-duplex, which can travel information in both directions at once, serial devices use them to enable each device to transmit and receive data.
The performance of the serial ports is reliant on the Universal Asynchronous Receiver/Transmitter (UART), a controller chip. With the aid of a serial port, the UART chip converts the parallel output received by the computer’s system bus into serial form for transmission. Most UART chips include a built-in buffer of 16 to 64 kilobytes in order to operate quickly. The chip can cache data from the system bus even though this buffer processing data is sent out to the serial port. Two high-tech serial ports that can transfer data at 460 kilobits per second are the Enhanced Serial Port and the Super Enhanced Serial Port. On the other hand, the majority of standard serial ports have a data transfer rate of 115 Kbps.