What is serial communication?
Serial communication is a data transmission method that sends information one by one of the device to the device. Over the years, many different serial standards have been developed for both low speed bandwidth and high -speed devices. Data can usually be replaced at much greater distances using a series than parallel communication. Serial communication is usually used to connect printers, terminals and cameras to computers. It is also used to connect to external hard drives, digital video disks (DVDs) and Flash memory device. A very minimal connection can include only one wire for data and the other for the ground link. In practice, many serial links also include several handsharing signals as well as the data line in each direction. Universal serial bus (USB), commonly used to connect computers and peripherals, uses only four or Five signals, two of which are for power. Recommended Standard (RS) 232 Serial Connection can be used up to 20 signals, depending onSti for implementation.
Fewer signals generally allow the serial communication connection to be faster and more reliably operate over long distances. Parallel communication can introduce chamfers or interference between data bits when they travel together after a long link. Serial connection RS 232 1,000 feet (300 meters) or longer can usually be operated on more than 115 200 bits per second. In contrast, USB 2.0 links are often used to connect storage devices with high bandwidth to computer systems. In general, they can exchange data of up to 480 megabites per second, but the cables are limited to 16 feet (5 meters).
When data is transmitted across a serial link, the receiver must have a way to find out when each byte will end and another will begin. In the asynchronous series communication, the sender inserts a bit "Start" before sending the bits of each byte. Initial bit also synchronizes the inner clock, ktEré helps to divide the rest of the received frame into individual bits. This is the most commonly used Method of Synchronization of RS 232. A separate clock signal is used in synchronous series communication to indicate where each bit and byte are completed.
Before starting the RS 232 data, the device must be set on both sides to use the same number of stop data and bits and the same type of parity. Eight bits, one bit stop and no parity is a frequent configuration, commonly expressed as 8n1. If Mark or Space is used, a parity bit is adjusted to one or zero by the sender. If uniform or special parity is used, the parity bit is set to a value that will make the total number of one bits or odd. The receiver checks the value of the parity bits received, if any, and indicates an error if the anneap is the expected value.
In addition to checking parity, one or more software serial communication protocols can be used to protectItem before data transfer errors. For example, XMOD or Modem is often used for file transmission between computers via serial link RS 232. These protocols were originally designed to be used with a modem based on a phone phone at each end of the link, but also work without them. Each protocol contains verification of the control sum of the cyclic redundancy (CRC) calculated for the data sent. If modems are present, they also perform similar CRC checks in hardware during transmission.