Serial communication is a communication technique used in telecommunications wherein data transfer occurs by transmitting data one bit at a time in a sequential order over a computer bus or a communication channel. It is the simplest form of communication between a sender and a receiver. Because of the synchronization difficulties involved in parallel communication, along with cable cost, serial communication is considered best for long-distance communication.
Techopedia explains Serial Communication
In contrast to parallel communication, which is half duplex, serial communication is full duplex, i.e., transmission and receipt of signals can occur simultaneously. It is the most popular mode of communication protocol for most instrumentation devices. It is also popular in computer devices, peripheral devices and integrated circuits, which are provided with one or more serial ports, resulting in no additional hardware requirements for serial communication.
There are several advantages with serial communication. As there are fewer conductors in contrast to parallel communication, the cross-talk issue is significantly less. Interconnecting cables are fewer, and there is no need for a serializer/deserializer in any case. The data transfer rate, however, may be low in comparison to parallel communication. Nevertheless, the clock skew problem that often happens between different channels of communication is not an issue with serial communication.
Compared to parallel communication, serial communication has better signal integrity. In addition, serial communication is one of the cheapest modes of communication that can be implemented, and over long-haul communication, it can provide numerous benefits.