In telecommunication and computer science, serial communication is the process of sending data one bit at one time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where all the bits of each symbol are sent together. Serial communication is used for all long-haul communication and most computer networks, where the cost of cable and synchronization difficulties make parallel communication impractical. Serial computer buses are becoming more common as improved technology enables them to transfer data at higher speeds.