Difference Between Parallel and Serial Communication

Difference between parallel and  serial communication

The basic difference between a parallel and a serial communication is structure of channel where a parallel cable can carry multiple bits at the same time, one for each cable. Where serial transmission occurs over a single cable, one bit at a time. Parallel interface would be the 8+ lane like  mega-highway and on the other hand  serial interface have a two-lane as a normal road. Parallel connections  are faster due to a higher rate of transfer. However parallel ports also require more hardware making them more expensive to implement but on the other hand  serial  communication  easy to established and no extra devices are used because  most of  computers have one or more serial ports.

Serial communication example


Rs-232 is a standard for serial communication transmission of data. Rs-232 is abbreviated from recommend  standard number 232 and c is the latest revision of the standard. The serial ports on most computers use a subset of the rs-232c standard. Although serial transmission only one wire is used for data transfer but rs-232 cable can theoretically accommodate 25 wires but most of these pins are not needed for normal pc communications, and indeed, most new PCS are equipped with male d type connectors having only 9 pins. One of the most visible example is a serial pc mouse.

Universal serial bus

In information technology, universal serial bus (USB) is a serial bus standard to connect devices to a host computer. USB was designed to allow many peripherals to be connected using a single standardized interface socket. That is, by allowing devices to be connected and disconnected without rebooting the computer or turning off the device. USB is intended to replace many varieties of serial and parallel ports. USB can connect computer peripherals such as mice, keyboards, joysticks, scanners, digital cameras, printers, personal media players, flash drives, and external hard drives. For many of those devices, USB has become the standard connection method.


Rs-423 is replacement of  the older rs-232 serial communication. The rs-423 standard defines a UNI-directional interface between one transmitter and many receivers. Rs-423 allows for distances up to 4000 feet but it is limited data transfer rates of 100 kb/sec.

PCI express

Peripheral component interconnect express also abbreviated as PCIE PCI express protocol is a computer expansion card standard designed to replace the older PCI or PCI-x, and AGP standards. PCI express is a serial connection that operates more like a network than a bus. Instead of one bus that handles data from multiple sources, PCIE has a switch that controls several point-to-point serial connections.

Examples of parallel communication

Industry standard architecture (ISA)

ISA stand for industry standard architecture is a type of bus used in PCS for adding expansion cards. Isa slot is used  for  video card, a network card, or an extra serial port. To days ISA ports were replaced by faster PCI and AGP and PCI-E slots.

Parallel  ATA

PATA short for parallel ATA  parallel ATA (PATA) is an interface standard for the connection of storage devices such as hard disks, solid-state drives, and CD-ROM drives in computers. In earlier days PATA was only called ATA which is renamed to parallel ATA when the newer serial ATA (SATA) standard came into being. Normally PATA cable connected form one to pc board which is called IDE connecter and other to storage device for example hard disk.

IEEE 1284

The IEEE 1284 parallel interface standard is the prevalent standard for connecting a computer to a printer or certain other devices over a parallel (eight bits of data at a time) physical and electrical interface . The maximum speed that is allow over the new IEEE parallel bus is 2 mbps (16 mbps)

Conventional PCI

Conventional PCI often called PCI derived from peripheral component interconnect is a computer port for attaching different hardware devices in a computer. The PCI standards include a full plug-and-play capability. This means the computer bios or operating system can determine the resource requirements.

Element of data communication (simplified model of communication)

Following are the some elements of data communication:


There are many factors, which influence the communication process, all of which impact each other in a variety of ways. This model shows how the most important factors function in what would be a snapshot of a static instance of communication.


The message generated by a device is called source, computer, and telephone. We can also say that information sent out through the system is called source. The source information may include numbers, words, photos, other graphics, sounds and video.


The data transmission device is called sender some time called transmitter, this device convert the data electromagnetic or electrical signal by modem.


The way through which the message is travel is called medium. It is the physical path between transmitter & receiver in data transmission system, you can send a letter to your friend then you are sender and your friend is receiver & the postal service is medium.


The computer/ device that receives the data is called receiver. Many devices act like sender and  also receiver.


The intended device where the data is to be received is called destination.



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