Serial vs Parallel Communication Protocols - ATM | DigiKey

Serial and parallel communication protocols differ in the way they transmit data between devices or systems. Serial communication protocols, such as RS-232, USB, and I2C, transmit data sequentially, one bit at a time, over a single communication channel. This approach is simpler and requires fewer physical connections, making it cost-effective and easier to implement, especially over long distances. However, serial communication can be slower than parallel communication, as data transfer is limited by the speed of the single channel. In contrast, parallel communication protocols, such as SCSI (Small Computer System Interface) and PCI (Peripheral Component Interconnect), transmit data simultaneously over multiple parallel channels or wires. This allows for faster data transfer rates, as multiple bits can be transmitted concurrently. Parallel communication is particularly useful for applications that require high-speed data transfer, such as data storage devices, high-performance computing systems, and certain types of computer peripherals. However, parallel communication requires more physical connections and can be more complex to implement, especially over longer distances, due to potential synchronization issues and signal interference. Related URL: https://www.digikey.com/en/application-technology/sensors Learn more: Maker.io - https://www.digikey.com/en/maker DigiKey’s Blog – TheCircuit https://www.digikey.com/en/blog Connect with DigiKey on Facebook https://www.facebook.com/digikey.electronics/ And follow us on X (Formerly Twitter) https://twitter.com/digikey Full transcription: Serial and parallel transmissions are communication protocols used to transmit data between digital devices. Serial communication sends one bit of data at a time using only one wire and is used to transmit over long distances. It is a preferred choice when a low cost option is required, and higher speeds offered by parallel communication aren't required. There are two subcategories of serial communication; synchronous and asynchronous. The distinction between the two is determined by the presence or absence of a clock signal. If a clock signal is present in the connected devices to control communication, then it is a synchronous serial transmission. If no clock signal is present, the transmission is asynchronous. With synchronous transmission, the time interval is constant and communication is faster, while asynchronous is randomly triggered by special signals in the transmission and communication is slower. Serial communication can be Simplex, Half-Duplex, or Full-Duplex. Simplex allows unit directional data transmission. Half duplex allows bidirectional data transmission, with only one device transmitting at a time. Full duplex allows bidirectional data transmission, with devices being able to send and receive data simultaneously. Examples of serial protocols include USB, SPI, I2C, CAN, Ethernet, and Uart. Parallel communication sends multiple bits of data simultaneously over shorter distances using data bus hardware and multiple wires. This can be more costly, but is ideal when multiple bits of data are needed to be transmitted quickly. Parallel transmission is typically synchronous and is half duplex. Examples of parallel protocols include PCI, SCSI, and IEE-488. To Learn more about these protocols and communication types head to digikey.com and check out our sensors, applications and Technology pages today.