Serial transmission

Serial transmission is when we have a single wire which we send data down, one bit at a time in a sequence (specific order).

Most peripherals use serial transmission, primarily the Universal Serial Bus (or whta you probably know as USB) which is used to connect loads of different devices to a computer.

Advantages of serial transmission

Compared to parallel transmission, serial transmission has a few advantages:

• It’s cheaper to implement as it only requires one wire (or a few wires for power and ground, and maybe one each direction).
• It’s more reliable as there is less chance of interference between the wires (called crosstalk).
• It can be used over longer distances as the signal is less likely to degrade over a single wire.
• Sometimes, it can actually be faster than parallel transmission, as the wires can be run at a higher frequency without interference.
• There’s no skew issues, because the bits are sent one after another in order, so don’t get out of sync.
• It’s easier to implement error detection and correction, as the bits are sent in a known order, so it’s easier to detect if a bit is missing or corrupted.
• (Among a vast number of other benefits)

Disadvantages of serial transmission

The main disadvantage of serial transmission compared to parallel transmission is that it can be slower than parallel in some cases, as it sends bits one at a time, whereas parallel can send multiple bits at once. However, as mentioned above, this isn’t always the case, because parallel can be slowed down by various different things.

Examples of serial transmission

• USB (Universal Serial Bus)
• UART (Universal Asynchronous Receiver Transmitter)
• SPI (Serial Peripheral Interface)
• Ethernet (wired networking)
• Wi-Fi (wireless networking) is usually serial