The list of hardware components that may be purchased and utilized with your serial port is shown below. One of the most prevalent serial port devices, typically used with computers lacking PS/2 or USB ports and specialist mice. The modem is another device that is typically used with serial ports. Modems usually connect to your telephone line to provide Internet access through your computer.
The table shows some common modems and their associated manufacturers. Not all modems will work with every manufacturer's product, so make sure you test drive any new component before installing it in your computer.
Modems usually have a separate receiver/decoder which connects to the computer's serial port. Some receivers require additional drivers installed within the operating system while others do not. Know what type of device you have before you start shopping for one that will work with your serial port.
A terminal program allows you to communicate via serial port by typing and downloading data from your port. There are several free and paid-for programs available online and in store shelves today that provide this functionality. They range from simple ASCII characters to more advanced protocols such as RS-232 CTS, RTS, NLS, and NTP.
A printer communicates with your computer via its serial port. Printers are very easy to find on eBay and other online retailers; all you need to know is the model number to search for it.
The serial port was once found on practically all new PCs, however it is no more. As a result, as of 2008, it is becoming, if not already, outdated. Although it is commonly referred to as a "legacy" device, it is still used by some for gear intended to connect to the serial port, particularly for computers used as servers by businesses.
USB Connectivity (Universal Serial Bus) These can connect practically any device, including mice, keyboards, printers, and digital cameras. They are frequently seen on the front and rear of the computer. USB ports operate at a speed of 1.5mA per port, with a maximum total current of 15mA per port. The USB standard was developed by Microsoft, Intel, and other technology companies.
PS/2 Connectivity A standard developed by IBM, these ports usually appear on high-end desktop computers and some laptops. They can be found on the back of most personal computers as well as some servers and workstations. PS/2 ports operate at a speed of 5 volts, with a maximum total current of 50mA per port. The PS/2 standard was developed around 1987 and remains in use today.
Parallel Port Connectivity A standard developed by Apple that remained popular until the introduction of USB connectivity, these ports can be found on the rear of most Apple Macintosh computers. They can also be found on many peripherals designed specifically for use with Macs. Parallel ports operate at a speed of 16 mA per port, with a maximum total current of 160 mA. The parallel port standard was introduced in 1980 and remains in use today.
To avoid confusion, the cables that transmit this data (other than "the" serial cable) and the computer ports into which they plug are frequently given a more particular name. Serial keyboard and mouse connections and ports, such as PS/2, Apple Desktop Bus, and USB, are virtually always used. Parallel printer connections and ports include Centronics and Lexmark.
A serial connection transmits one bit of data at a time, from transmitter to receiver. Each bit of data is called a "character." The characters are encoded on the line in a binary format: 0s and 1s. The sender converts each letter to be sent into its corresponding sequence of 0s and 1s; these sequences are called "bytes." On the receiving end, the byte stream is converted back into letters.
A parallel connection sends several bits of data simultaneously. Each "word" of data consists of 8 bits, so parallel interfaces can transfer up to 255 bytes per word. The term "byte" is still used for the individual units of information transferred over a parallel interface, but only 7 of those bytes are actually transmitted during a single transfer cycle. The extra bit transfers through the interface automatically, either when you connect two devices together or when you send a command to a device.
So, a serial port is one that uses just a single wire to transfer data, whereas a parallel port uses many wires.
Although USB ports are rarely used in older devices, they are used to transport data by the majority of current computers. You may continue to utilize your older serial-enabled device through your new computer's USB port by utilizing a USB to serial converter. When data is delivered over the USB interface, it arrives as a serial signal. Therefore, a USB to serial adapter can be used to convert data being sent serially via a cable to the old device into digital signals that can be read by its controller.
A USB to serial adapter is useful for communicating with devices that use serial interfaces such as modems, scanners, and printers. It allows you to connect these devices directly to a computer without having to use a universal serial bus (USB) port on the computer itself. A USB to serial adapter consists of a USB hub or other device that connects to a computer's USB port and a corresponding serial port connector. The adapter then enables communication between the connected devices and the computer via their respective serial ports.
Most modern USB to serial adapters operate at speeds up to 115200 bps using either DB9 or COM ports as standard interfaces. However, some lower speed devices may also be compatible with certain models of USB to serial adapters. For example, many low speed modems operate at 9600 bps, which would be supported by an adapter capable of handling modems up to 38400 bps.
There are several types of USB to serial adapters available on the market today.