Serial port
The serial interface is used to exchange data between computers and peripheral devices. In serial data transmission, the bit order ( serially ) to be transmitted via a line. When speaking without further identification of a " serial port ", so that the CCITT V.24 or EIA RS232 interface is almost always meant. The meaning and arrangement of the bits is specified in the RS- 232 with a so-called UART ( Universal Asynchronous Receiver Transmitter ) or USART (Universal Synchronous Asynchronous Receiver Transmitter ). Modern serial interfaces are Ethernet, USB, Firewire, CAN bus or RS- 485, but these are not commonly referred to as serial interfaces.
RS- 232 was originally developed in the 1960s as an interface for data transmission to terminals from paper tape reader and writer and an input device that closely resembled a remote Scheiber passed. Display terminals, there was only much later, however, they also up in the 1980's into it was because the computer usually have no own screen edition. The serial RS232 interface also operated modems, which implemented messages for transmission on telephone lines. Largest gained popularity this interface for networking of terminals ( eg VT100 ) with host computers, notably the DEC. The RS232 interface is also used in the CAD systems to ( Tektronix ) with quick mainframes to connect graphical terminals. Since only telephone lines for remote transmission of data were in the 1980s (eg BTX) are available whose Übertragungsrateauf was limited to the downlink 1200bps and 75Bps on the uplink (upper cut-off frequency around 3500 Hz ), RS -232 has been tailored accordingly. The adjustable data rates were 110-19200 bits per second ( b / s). Only with the use of a terminal interface, the need grew for higher data rates, today 19200 kilobits per second were given in general. In this moderate transmission speed you can do without the handshake lines and work with XON / XOFF protocol which the cabling between data communications equipment (DCE ) and data receiving device (DTE ) is reduced to a minimum. While the original interface definition 25 - pin sockets are provided for (because the handshake signals ), the interface was implemented 9-pin in the 1990s (especially on the PC). They renounced to the cables, which were necessary for synchronous data transmission, since this type of transmission i82c50 (and its known derivatives NS16C550 ) do not support the commonly used UART type this mode.
For the transmission of high data rates over short distances, the so-called parallel interface ( Centronics, ECP, EPP ) prevailed against it before serial and parallel interfaces have been largely superseded by USB.
Standards
There are several standards that specify the types of serial transmission. These include:
- EIA- 232 (RS -232, V.10 ) - 1962 introduced serial interface
- EIA- 422 ( RS -422, V.11 ) - differential transmitter and receiver
- EIA -423 (RS -423, V.10 ) - asymmetric interface similar to RS232
- EIA- 485 ( RS- 485, V.11 ) - differential transceiver ( erroneously referred to as a party line )
- Party Line - differential transmitters and receivers with each additional ground line (6- wire )
- Low Voltage Differential Signaling (LVDS, EIA -644 ) - see RS -422
- TTY interface (Current - loop)
- I ² C- bus - For communication within a single device, with a data and a clock signal, for example, at telephone calling
- I ² S bus - for the exchange of audio data ( Inter-IC Sound interface), for example, ADC signal processor → → DAC
- Serial Peripheral Interface (SPI) - for communication within a device, with a data and clock signal, for example, serial flash memory
- 1-Wire bus - For communication within a device or between several proprietary devices via a data line (eg, MDA, PDA and battery)
- Serial ATA ( S -ATA) - for connection to the PC's hard drive.
- Serial Attached SCSI ( SAS) - for connection to SAS hard drives.
- PCI Express - new standard PC, replaced the parallel data buses AGP and PCI
- FireWire (i.LINK or IEEE 1394) - for example, for hard disks, audio and video data
- Universal Serial Bus (USB)
- PS / 2 - Mini -Din connector ( formerly DIN ) for mouse and keyboard for PCs
- CBM bus - an adapted by Commodore Business Machines Bit serial bus in accordance with the IEC 625 bus
- Digital Visual Interface (DVI) - transmission of video data
- High Definition Multimedia Interface (HDMI) - Digital transmission of audio and video
- RC5 code - Infrared transmission standard for remote controls
- Infrared Data Association (IrDA ) - Standard for IR communication between laptops, cell phones, etc.
- Bluetooth - Wireless network standard for smaller distances for headset, mobile phone, laptop
- Unilink - developed by Sony proprietary vehicle infotainment interface
- MIDI - musical instruments for
- To host - see also MIDI, MP3
- DMX - stage equipment, lighting
- Sony / Philips Digital Interface (S / PDIF, TOSLINK) - for audio data in the consumer sector
- AES / EBU ( AES3 ) - for audio data in the study area, see also S / PDIF
- Controller Area Network (CAN- bus ) - Control Engineering, Automotive Engineering
- Profibus - industrial bus from the automation control
- DIN measuring bus - fieldbus for automation technology
- Multi Point Interface (MPI) - for automation technology from Siemens
- Interbus -S - fieldbus for automation technology from Phoenix Contact
- BITBUS - Fieldbus IEEE 1118
- Party Line - Fieldbus for terminals operating data of INCA
- Local Operating Network ( LON) - also automation technology
- S0 bus - terminal interface for ISDN (digital wide area network; telephony)
- Ethernet - Networks & Internet
- Wireless LAN ( WLAN) - wireless local area network IEEE 802.11
- FlexRay - Automotive
- AS-Interface - Fieldbus for connecting actuators and sensors