Communication between two machines requires a transfer of signal from an output to an input. There needs to be a sender and receiver of the signal for the complete communication process to take place. Serial and parallel communications are both ways of transferring data over networks. Both systems have a unique way of operating, with differences between the two ranging from the mode of relaying signals to the level of connectivity they require.
A serial communication device transfers data in bits in the same direction. A parallel communication device sends data in multiple bits to the same direction. In serial communication a word of eight bits in length is sent sequentially, and is received after all eight bits are sent, one at a time. The bits are then assembled back into one byte which is the initial communication. In parallel communication the eight bits are transferred in corresponding 8 channels, every channel transmits a bit, and a byte of data is received simultaneously.
Parallel communication devices are faster than their serial counterparts. A serial communication device sends data in bits, and at the end the bits harmonize to form a byte of data. A parallel communication device sends and receives the same amount of data simultaneously, thus making it faster. The parallel device has eight wires connected to the port which transmits all the 8 bits through the eight wire connectors simultaneously. This means that a parallel device transmits an 8 bits data within the same time a serial device transmits a single bit.
Serial communication uses fewer connections and cables than parallel communication does. The use of fewer wires in serial communication makes its signals clearer, thus making it suitable for long distance communication. Parallel communication uses more wires to allow the transfer of data simultaneously. The use of many wires causes the signals to become distorted, making parallel communication unsuitable for long distance transmission.
Cost and Space
Serial communication has a single port with a connector while a parallel port is usually connected to eight wires. A serial port therefore, requires less investment for purchasing wires compared to parallel communication. In terms of space, parallel communication requires more space to accommodate its wires while serial communication utilizes minimal space for its single connector.