Misplaced Pages

Serial communication: Difference between revisions

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
Browse history interactively← Previous editNext edit →Content deleted Content addedVisualWikitext
Revision as of 12:16, 12 June 2014 editClueBot NG (talk | contribs)Bots, Pending changes reviewers, Rollbackers6,438,688 editsm Reverting possible vandalism by 37.191.124.14 to version by Mmpozulp. False positive? Report it. Thanks, ClueBot NG. (1872969) (Bot)← Previous edit Revision as of 10:30, 7 July 2014 edit undo122.3.45.162 (talk) →Cables that carry serial dataTag: possible vandalismNext edit →
Line 7: Line 7:
{{main| data cable}} {{main| data cable}}
Many serial communication systems were originally designed to transfer data over relatively large distances through some sort of ]. Many serial communication systems were originally designed to transfer data over relatively large distances through some sort of ].
tang ina mo

The term "serial" most often refers to the RS232 port on the back of the original ], often called "the" ], and "the" ] designed to plug into it, and the many devices designed to be compatible with it. The term "serial" most often refers to the RS232 port on the back of the original ], often called "the" ], and "the" ] designed to plug into it, and the many devices designed to be compatible with it.


Revision as of 10:30, 7 July 2014

This article does not cite any sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.
Find sources: "Serial communication" – news · newspapers · books · scholar · JSTOR (July 2013) (Learn how and when to remove this message)

In telecommunication and computer science, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels.

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 even at shorter distances, as improved signal integrity and transmission speeds in newer serial technologies have begun to outweigh the parallel bus's advantage of simplicity (no need for serializer and deserializer, or SerDes) and to outstrip its disadvantages (clock skew, interconnect density). The migration from PCI to PCI Express is an example.

Cables that carry serial data

Main article: data cable

Many serial communication systems were originally designed to transfer data over relatively large distances through some sort of data cable. tang ina mo The term "serial" most often refers to the RS232 port on the back of the original IBM PC, often called "the" serial port, and "the" serial cable designed to plug into it, and the many devices designed to be compatible with it.

Practically all long-distance communication transmits data one bit at a time, rather than in parallel, because it reduces the cost of the cable. The cables that carry this data (other than "the" serial cable) and the computer ports they plug into are usually referred to with a more specific name, to reduce confusion.

Keyboard and mouse cables and ports are almost invariably serial -- such as PS/2 port and Apple Desktop Bus and USB.

The cables that carry digital video are almost invariably serial -- such as coax cable plugged into a HD-SDI port, a webcam plugged into a USB port or Firewire port, Ethernet cable connecting an IP camera to a Power over Ethernet port, FPD-Link, etc.

Other such cables and ports, transmitting data one bit at a time, include Serial ATA, Serial SCSI, Ethernet cable plugged into Ethernet ports, the Display Data Channel using previously reserved pins of the VGA connector or the DVI port or the HDMI port.

Serial buses

Many communication systems were generally originally designed to connect two integrated circuits on the same printed circuit board, connected by signal traces on that board (rather than external cables).

Integrated circuits are more expensive when they have more pins. To reduce the number of pins in a package, many ICs use a serial bus to transfer data when speed is not important. Some examples of such low-cost serial buses include SPI, I²C, UNI/O, and 1-Wire.

Serial versus parallel

The communication links across which computers—or parts of computers—talk to one another may be either serial or parallel. A parallel link transmits several streams of data simultaneously along multiple channels (e.g., wires, printed circuit tracks, or optical fibres); a serial link transmits a single stream of data.

Although a serial link may seem inferior to a parallel one, since it can transmit less data per clock cycle, it is often the case that serial links can be clocked considerably faster than parallel links in order to achieve a higher data rate. A number of factors allow serial to be clocked at a higher rate:

  • Clock skew between different channels is not an issue (for unclocked asynchronous serial communication links).
  • A serial connection requires fewer interconnecting cables (e.g., wires/fibres) and hence occupies less space. The extra space allows for better isolation of the channel from its surroundings.
  • Crosstalk is less of an issue, because there are fewer conductors in proximity.

In many cases, serial is a better option because it is cheaper to implement. Many ICs have serial interfaces, as opposed to parallel ones, so that they have fewer pins and are therefore less expensive.

Examples of serial communication architectures

See also

External links

Technical and de facto standards for wired computer buses
General
Standards
Storage
Peripheral
Audio
Portable
Embedded
Interfaces are listed by their speed in the (roughly) ascending order, so the interface at the end of each section should be the fastest.
Category
Line coding (digital baseband transmission)
Main articles
Basic line codes
Extended line codes
Optical line codes
Categories: