What is a sophisticated printer used to produce high-quality drawings such as blueprints maps and circuit diagrams?

Computer output device that draws lines on paper by moving a pen

For other uses, see Plotter (disambiguation).

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Plotter" – news · newspapers · books · scholar · JSTOR (September 2009) (Learn how and when to remove this template message)

A plotter is a machine that produces vector graphics drawings. Plotters draw lines on paper using a pen, or in some applications, use a knife to cut a material like vinyl or leather. In the latter case, they are sometimes known as a cutting plotter.

In the past, plotters were used in applications such as computer-aided design, as they were able to produce line drawings much faster and of a higher quality than contemporary conventional printers. Smaller desktop plotters were often used for business graphics. Printers with graphics capabilities took away some of the market by the early 1980s, and the introduction of laser printers in the mid-1980s largely eliminated the use of plotters from most roles.

Plotters retained a niche for producing very large drawings for many years, but have now largely been replaced by wide-format conventional printers. Cutting plotters remain in use in a number of industries.

Overview

Digitally controlled plotters evolved from earlier fully analog XY-writers used as output devices for measurement instruments and analog computers.

Pen plotters print by moving a pen or other instrument across the surface of a piece of paper. This means that plotters are vector graphics devices, rather than raster graphics as with other printers. Pen plotters can draw complex line art, including text, but do so slowly because of the mechanical movement of the pens. They are often incapable of efficiently creating a solid region of color, but can hatch an area by drawing a number of close, regular lines.

Plotters offered the fastest way to efficiently produce very large drawings or color high-resolution vector-based artwork when computer memory was very expensive and processor power was very limited, and other types of printers had limited graphic output capabilities.

Pen plotters have essentially become obsolete, and have been replaced by large-format inkjet printers and LED toner-based printers. Such devices may still understand vector languages originally designed for plotter use, because in many uses, they offer a more efficient alternative to raster data.

X–Y plotter

An X–Y plotter is a plotter that operates in two axes of motion ("X" and "Y") in order to draw continuous vector graphics. The term was used to differentiate it from standard plotters which had control only of the "y" axis, the "x" axis being continuously fed to provide a plot of some variable with time. Plotters differ from Inkjet and Laser printers in that a plotter draws a continuous line, much like a pen on paper, while inkjet and laser printers use a very fine matrix of dots to form images, such that while a line may appear continuous to the naked eye, it in fact is a discrete set of points.

Electrostatic plotters

Electrostatic plotters used a dry toner transfer process similar to that in many photocopiers. They were faster than pen plotters and were available in large formats, suitable for reproducing engineering drawings. The quality of image was often not as good as contemporary pen plotters. Electrostatic plotters were made in both flat-bed and drum types. The electrostatic plotter uses the pixel as a drawing means, like a raster graphics display device. The plotter head consists of a large number of tiny styluses (as many as 21760) embedded in it. This head traverses over the width of the paper as it rolls past the head to make a drawing. The resolutions available may be 100 to 508 dots per inch. Electrostatic plotters are very fast with plotting speed of 6 to 32 mm/s, depending on the plotter resolution.[1]

Cutting plotters

Cutting plotters use knives to cut into a piece of material (such as paper, mylar film, or vinyl film) that is lying on the flat surface area of the plotter. The cutting plotter is connected to a computer, which is equipped with cutting design or drawing computer software programs. Those computer software programs are responsible for sending the necessary cutting dimensions or designs in order to command the cutting knife to produce the correct project cutting needs.[2]

In recent years the use of cutting plotters (generally called die-cut machines) has become popular with home enthusiasts of paper crafts such as cardmaking and scrapbooking. Such tools allow desired card and decal shapes to be cut out very precisely, and repeatably.

Languages

A number of printer control languages were created to operate pen plotters, and transmit commands like "lift pen from paper", "place pen on paper", or "draw a line from here to here". Three common ASCII-based plotter control languages are Hewlett-Packard's HP-GL, its successor HP-GL/2, and Houston Instruments DMPL. Here is a simple HP-GL script drawing a line:

This program instructs the plotter, in order, to take the first pen (SP1 = Select Pen 1), to go to coordinates X=500, Y=500 on the paper sheet (PA = Plot Absolute), to lower the pen against the paper (PD = Pen Down), to move 1000 units in the Y direction (thus drawing a vertical line - PR = Plot Relative), to lift the pen (PU = Pen Up) and finally to put it back in its stall.

Programmers using FORTRAN or BASIC generally did not program these directly, but used software packages, such as the Calcomp library, or device independent graphics packages, such as Hewlett-Packard's AGL libraries or BASIC extensions or high end packages such as DISSPLA. These would establish scaling factors from world coordinates to device coordinates, and translate to the low level device commands. For example, to plot X*X in HP 9830 BASIC, the program would be

10 SCALE -1,1,1,1 20 FOR X = -1 to 1 STEP 0.1 30 PLOT X, X*X 40 NEXT X 50 PEN 60 END

History

One of the earliest plotter was Konrad Zuse's computer-controlled and transistorized Graphomat Z64 in 1958, also shown at the Hannover Messe in 1961.[3]

Early pen plotters, e.g., the Calcomp 565 of 1959, worked by placing the paper over a roller that moved the paper back and forth for X motion, while the pen moved back and forth on a track for Y motion. The paper was supplied in roll form and had perforations along both edges that were engaged by sprockets on the rollers.

Another approach, e.g. Computervision's Interact I, involved attaching ball-point pens to drafting pantographs and driving the machines with stepper motors controlled by the computer. This had the disadvantage of being somewhat slow to move, as well as requiring floor space equal to the size of the paper, but could double as a digitizer. A later change was the addition of an electrically controlled clamp to hold the pens, which allowed them to be changed, and thus create multi-colored output.

Hewlett Packard and Tektronix produced small, desktop-sized flatbed plotters in the late 1960s and 1970s. The pens were mounted on a traveling bar, whereby the y-axis was represented by motion up and down the length of the bar and the x-axis was represented by motion of the bar back and forth across the plotting table. Due to the mass of the bar, these plotters operated relatively slowly.

In the 1980s, the small and lightweight HP 7470 introduced the "grit wheel" mechanism, eliminating the need for perforations along the edges, unlike the Calcomp plotters two decades earlier. The grit wheels at opposite edges of the sheet press against resilient polyurethane-coated rollers and form tiny indentations in the sheet. As the sheet is moved back and forth, the grit wheels keep the sheet in proper registration due to the grit particles falling into the earlier indentations, much like the teeth of two gears meshing. The pen is mounted on a carriage that moves back and forth in a line between the grit wheels, representing the orthogonal axis. These smaller "home-use" plotters became popular for desktop business graphics and in engineering laboratories, but their low speed meant they were not useful for general printing purposes, and different conventional printer would be required for those jobs. One category, introduced by Hewlett Packard's MultiPlot for the HP 2647, was the "word chart", which used the plotter to draw large letters on a transparency. This was the forerunner of the modern Powerpoint chart. With the widespread availability of high-resolution inkjet and laser printers, inexpensive memory and computers fast enough to rasterize color images, pen plotters have all but disappeared. However, the grit wheel mechanism is still found in inkjet-based, large format engineering plotters.

Plotters were also used in the Create-A-Card kiosks that were available for a while in the greeting card area of supermarkets that used the HP 7475 six-pen plotter.

Plotters are used primarily in technical drawing and CAD applications, where they have the advantage of working on very large paper sizes while maintaining high resolution. Another use has been found by replacing the pen with a cutter, and in this form plotters can be found in many garment and sign shops.

Changing the color or width of a line required the plotter to change pens. This was either done manually on small plotters, but more typically the plotter would have a magazine of four or more pens which could be automatically mounted.

A niche application of plotters is in creating tactile images for visually handicapped people on special thermal cell paper.

Unlike other printer types, pen plotter speed is measured by pen speed and acceleration rate, instead of by page printing speed. A pen plotter's speed is primarily limited by the type of pen used, so the choice of pen is a key factor in pen plotter output speed. Indeed, most modern pen plotters have commands to control slewing speed, depending on the type of pen currently in use.

There are many types of plotter pen, some of which are no longer mass-produced. Technical pen tips are often used, many of which can be renewed using parts and supplies for manual drafting pens. Early HP flatbed and grit wheel plotters used small, proprietary fiber-tipped or plastic nib disposable pens.

One type of plotter pen uses a cellulose fiber rod inserted through a circular foam tube saturated with ink, with the end of the rod sharpened into a conical tip. As the pen moves across the paper surface, capillary wicking draws the ink from the foam, down the rod, and onto the paper. As the ink supply in the foam is depleted, the migration of ink to the tip begins to slow down, resulting in faint lines. Slowing the plotting speed will allow the lines drawn by a worn-out pen to remain dark, but the fading will continue until the foam is completely depleted. Also, as the fiber tip pen is used, the tip slowly wears away on the plotting medium, producing a progressively wider, smudged line.

Ball-point plotter pens with refillable clear plastic ink reservoirs are available. They do not have the fading or wear effects of fiber pens, but are generally more expensive and uncommon. Also, conventional ball-point pens can be modified to work in most pen plotters.

Vinyl cutter

A vinyl cutter (sometimes known as a cutting plotter) is used to create posters, billboards, signs, T-shirt logos, and other weather-resistant graphical designs. The vinyl can also be applied to car bodies and windows for large, bright company advertising and to sailboat transoms. A similar process is used to cut tinted vinyl for automotive windows.

Colors are limited by the collection of vinyl on hand. To prevent creasing of the material, it is stored in rolls. Typical vinyl roll sizes are 15-inch, 24-inch, 36-inch and 48-inch widths, and have a backing material for maintaining the relative placement of all design elements.

Vinyl cutter hardware is similar to a traditional plotter except that the ink pen is replaced by a very sharp knife to outline each shape, and may have a pressure control to adjust how hard the knife presses down into the vinyl film, preventing the cuts from also penetrating the backing material. Besides losing relative placement of separate design elements, loose pieces cut out of the backing material may fall out and jam the plotter roll feed or the cutter head. After cutting, the vinyl material outside of the design is peeled away, leaving the design on the backing material which can be applied using self-adhesion, glue, lamination, or a heat press.

The vinyl knife is usually shaped like a plotter pen and is also mounted on a swivel head so that the knife edge self-rotates to face the correct direction as the plotter head moves.

Vinyl cutters are primarily used to produce single-color line art and lettering. Multiple color designs require cutting separate sheets of vinyl, then overlaying them during application; but this process quickly becomes cumbersome for more than a couple of hues.

Sign cutting plotters are in decline in applications such as general billboard design, where wide-format inkjet printers that use solvent-based inks are employed to print directly onto a variety of materials. Cutting plotters are still relied upon for precision contour-cutting of graphics produced by wide-format inkjet printers – for example to produce window or car graphics, or shaped stickers.

Large-format inkjet printers are increasingly used to print onto heat-shrink plastic sheeting, which is then applied to cover a vehicle surface and shrunk to fit using a heat gun, known as a vehicle wrap.

Static cutting table

A static cutting table is a type of cutting plotter used a large flat vacuum table. It is used for cutting non-rigid and porous material such as textiles, foam, or leather, that may be too difficult or impossible to cut with roll-fed plotters. Static cutters can also cut much thicker and heavier materials than a typical roll-fed or sheet-fed plotter is capable of handling.

The surface of the table has a series of small pinholes drilled in it. Material is placed on the table, and a coversheet of plastic or paper is overlaid onto the material to be cut. A vacuum pump is turned on, and air pressure pushes down on the coversheet to hold the material in place. The table then operates like a normal vector plotter, using various cutting tools to cut holes or slits into the fabric. The coversheet is also cut, which may lead to a slight loss of vacuum around the edges of the coversheet, but this loss is not significant.

Contemporary uses of pen plotters

In the mid-to-late 2000s artists and hackers[4][5] began to rediscover pen plotters as quirky, customizable output devices. The quality of the lines produced by pens on paper is quite different from other digital output techniques. Even 30-year-old pen plotters typically still function reliably, and many were available for less than $100 on auction and resale websites. While support for driving pen plotters directly or saving files as HP-GL has disappeared from most commercial graphics applications, several contemporary software packages[6][7][8][9] make working with HP-GL on modern operating systems possible.

As use of pen plotters has waned, the large-format printers that have largely replaced them have sometimes come to be called "plotters" as well.

See also

• Chart recorder
• Photoplotter
• Polar plotter

References

Wikimedia Commons has media related to Plotters.

1. ^ CAD/CAM Principles and application. P. N. RAO.
2. ^ "Cutting plotter". CUTCNC cam. 2011-10-09.
3. ^ Böttiger, Helmut (2011-10-26). "Der Erfinder - Kriegsbedingte Unterbrechung und Theorie". In Rabenseifner, Adolf (ed.). Konrad Zuse: Erfinder, Unternehmer, Philosoph und Künstler (in German) (1 ed.). Petersberg, Germany: Michael Imhof Verlag. pp. 37–43 [42–43]. ISBN 978-3-86568-743-2. pp. 42–43: Der erste Plotter Graphomat Z64: Die Rede war hier von der Entwicklung eines Zeichenhilfgerätes (Z60), aus dem dann um 1958 der Graphomat Z64 wurde, das erste computergesteuerte, mit Transistoren ausgestattete Zeichengerät (Plotter). Es wurde 1961 erfolgreich auf der Hannover-Messe vorgeführt. Es zeichnete sich durch eine hohe Zeichengenauigkeit von 1/16 mm und 16 verschiedene Zeichengeschwindigkeiten aus und öffnete der Datenverarbeitung im Bereich der Graphik neue Anwendungsbereiche. Auch die Computerkunst erhielt den Startschuss mit dieser Maschine. Denn ab 1965 wurde die Z64 in der Bekleidungsindustrie zur Erstellung von Druck- und Schnittmustern eingesetzt. An der Entwicklung des Gerätes war der "optisch" orientierte Konrad Zuse naturgemäß besonders engagiert beteiligt. Vom ihm stammte der Gedanke eines "Binärstufengetriebes". Dabei wurden über das Addiergerät 15 verschiedene im Binärsystem abgestimmte Geschwindigkeitsstufen zur Führung des Stiftes auf der Zeichenbrücke rechnerisch überlagert und über Kupplungen zu- und abgeschaltet. Mit Hilfe des Gerätes ließen sich aufgrund von Berechnungen unterschiedliche Kurven sehr genau zeichnen. (128 pages)
4. ^ "The Draftmasters" (video). Vimeo. 2009-05-12.
5. ^ "El Muro". Berlin: UDK. Archived from the original on 2007-06-12.
6. ^ "Chiplotle: an HPGL (Hewlett-Packard Graphics Language) Python API". Columbia.
7. ^ "Processing".
8. ^ "Hackaplot". HV‐A. Archived from the original on 2011-02-27. Retrieved 2010-11-18.
9. ^ "New Designjet Plotters Launches by HP in 2015". HP. 2015-11-25.

Look up plotter in Wiktionary, the free dictionary.

Retrieved from "https://en.wikipedia.org/w/index.php?title=Plotter&oldid=1113863715"

Page 2

6-pin mini-DIN connector for connecting keyboards and mice to a PC compatible computer

"PS/2 keyboard" and "PS/2 mouse" redirect here. For the keyboards normally supplied with IBM PS/2 computers, see Model M keyboard. For peripherals and game conversions for the video game console, see PlayStation 2.

The color-coded PS/2 connection ports (purple for keyboard and green for mouse)

1. ^ Keyboard and mouse ports may be combined into a single port which can be used to connect both by splitter cable.
2. ^ Sometimes, mouse Data for splitter cable.
3. ^ Sometimes, mouse Clock for splitter cable.

The PS/2 port is a 6-pin mini-DIN connector used for connecting keyboards and mice to a PC compatible computer system. Its name comes from the IBM Personal System/2 series of personal computers, with which it was introduced in 1987. The PS/2 mouse connector generally replaced the older DE-9 RS-232 "serial mouse" connector, while the PS/2 keyboard connector replaced the larger 5-pin/180° DIN connector used in the IBM PC/AT design. The PS/2 keyboard port is electrically and logically identical to the IBM AT keyboard port, differing only in the type of electrical connector used. The PS/2 platform introduced a second port with the same design as the keyboard port for use to connect a mouse; thus the PS/2-style keyboard and mouse interfaces are electrically similar and employ the same communication protocol. However, unlike the otherwise similar Apple Desktop Bus connector used by Apple, a given system's keyboard and mouse port may not be interchangeable since the two devices use different sets of commands and the device drivers generally are hard-coded to communicate with each device at the address of the port that is conventionally assigned to that device. (That is, keyboard drivers are written to use the first port, and mouse drivers are written to use the second port.[1])

Communication protocol

Each port implements a bidirectional synchronous serial channel.[2] The channel is slightly asymmetrical: it favors transmission from the input device to the computer, which is the majority case. The bidirectional IBM AT and PS/2 keyboard interface is a development of the unidirectional IBM PC keyboard interface, using the same signal lines but adding capability to send data back to the keyboard from the computer; this explains the asymmetry.[3]

The interface has two main signal lines, Data and Clock. These are single-ended signals driven by open-collector drivers at each end. Normally, the transmission is from the device to the host. To transmit a byte, the device simply outputs a serial frame of data (including 8 bits of data and a parity bit) on the Data line serially as it toggles the Clock line once for each bit. The host controls the direction of communication using the Clock line; when the host pulls it low, communication from the attached device is inhibited. The host can interrupt the device by pulling Clock low while the device is transmitting; the device can detect this by Clock staying low when the device releases it to go high as the device-generated clock signal toggles. When the host pulls Clock low, the device must immediately stop transmitting and release Clock and Data to both float high. (So far, all of this is the same as the unidirectional communication protocol of the IBM PC keyboard port, though the serial frame formats differ.) The host can use this state of the interface simply to inhibit the device from transmitting when the host is not ready to receive. (For the IBM PC keyboard port, this was the only normal use of signalling from the computer to the keyboard. The keyboard could not be commanded to retransmit a keyboard scan code after it had been sent, since there was no reverse data channel to carry commands to the keyboard, so the only way to avoid losing scan codes when the computer was too busy to receive them was to inhibit the keyboard from sending them until the computer was ready. This mode of operation is still an option on the IBM AT and PS/2 keyboard port.)[4]

To send a byte of data back to the device, the host pulls Clock low, waits briefly, pulls Data low and releases the Clock line again. The device then generates a Clock signal while the host outputs a frame of bits on the Data line, one bit per Clock pulse, similar to what the attached device would do to transmit in the other direction. However, while device-to-host transmission reads bits on falling Clock edges, transmission in the other direction reads bits on rising edges. After the data byte, the host releases the Data line, and the device will pull the Data line low for one clock period to indicate successful reception. A keyboard normally interprets the received byte as a command or a parameter for a preceding command. The device will not attempt to transmit to the host until both Clock and Data have been high for a minimum period of time.[5]

Transmission from the device to the host is favored because from the normal idle state, the device does not have to seize the channel before it can transmit—the device just begins transmitting immediately. In contrast, the host must seize the channel by pulling first the Clock line and then the Data line low and waiting for the device to have time to release the channel and prepare to receive; only then can the host begin to transmit data.

Port availability

PS/2 dualport, corresponding splitter (Y-cable) and pinout (female).

Older laptops and most contemporary motherboards have a single port that supports either a keyboard or a mouse. Sometimes the port also allows one of the devices to be connected to the two normally unused pins in the connector to allow both to be connected at once through a special splitter cable.[6] This configuration is common on IBM/Lenovo Thinkpad notebooks among many others.

The PS/2 keyboard interface is electrically the same as the 5-pin DIN connector on earlier AT keyboards, and keyboards designed for one can be connected to the other with a simple wiring adapter. Such wiring adapters and adapter cables were once commonly available for sale. Note that IBM PC and PC XT keyboards use a different unidirectional protocol with the same DIN connector as AT keyboards, so though a PC or XT keyboard can be connected to PS/2 port using a wiring adapter intended for an AT keyboard, the earlier keyboard will not work with the PS/2 port. (At least, it cannot work with normal PS/2 keyboard driver software, including the system BIOS keyboard driver.)

In contrast to this, the PS/2 mouse interface is substantially different from RS-232 (which was generally used for mice on PCs without PS/2 ports), but nonetheless many mice were made that could operate on both with a simple passive wiring adapter, where the mice would detect the presence of the adapter based on its wiring and then switch protocols accordingly.

PS/2 mouse and keyboard connectors have also been used in non-IBM PC-compatible computer systems, such as the DEC AlphaStation line, early IBM RS/6000 CHRP machines and SGI Indy, Indigo 2, and newer (Octane, etc.) computers.[7] Macintosh clone computers based on the "LPX-40" logic board design featured PS/2 mouse and keyboard ports, including the Motorola StarMax and the Power Computing PowerBase.[8]

Legacy port status and USB

PS/2 is now considered a legacy port, with USB ports now normally preferred for connecting keyboards and mice. This dates back at least as far as the Intel/Microsoft PC 2001 specification of 2000.

However, as of 2022, although PS/2 ports are rarely included in off the shelf computer systems, they continue to be included on many computer motherboards and are favored by some users for various reasons including the following:

• PS/2 ports may be favored for security reasons in a corporate environment as they allow USB ports to be totally disabled, preventing the connection of any USB removable disks and malicious USB devices.[9]
• The PS/2 interface provides no restriction on key rollover, although USB keyboards have no such restriction either, unless operated in BOOT mode, which is the exception.
• To free USB ports for other uses like removable USB devices.
• Some USB keyboards may not be able to operate the BIOS on certain motherboards due to driver issues or lack of support. The PS/2 interface has near-universal compatibility with BIOS.

Latency of mice

USB mice send data more quickly than PS/2 mice because standard USB mice are polled at a default rate of 125 hertz while standard PS/2 mice send interrupts at a default rate of 100 Hz when they have data to send to the computer. However, PS2 mice and keyboards are favored by many gamers because they essentially have zero latency through the port. There is no "polling" needed by the OS. The device notifies the OS when it's time to receive a packet of data from it.[10][11]

Also, USB mice do not cause the USB controller to interrupt the system when they have no status change to report according to the USB HID specification's default profile for mice.[12] Both PS/2 and USB allow the sample rate to be overridden, with PS/2 supporting a sampling rate of up to 200 Hz[2] and USB supporting a polling rate up to 1 kHz[10] as long as the mouse runs at full-speed USB speeds or higher.

USB key rollover limitations

The USB HID keyboard interface requires that it explicitly handle key rollover, with the full HID keyboard class supporting n-key rollover. However, the USB boot keyboard class (designed to allow the BIOS to easily provide a keyboard in the absence of OS USB HID support) only allows 6-key rollover. Some keyboard peripherals support only the latter class, and some OSes may fail to switch to using the full HID keyboard class with a device after boot.[13]

Conversion between PS/2 and USB

Many keyboards and mice were specifically designed to support both the USB and the PS/2 interfaces and protocols, selecting the appropriate connection type at power-on. Such devices are generally equipped with a USB connector and ship with a passive wiring adapter to allow connection to a PS/2 port. Such passive adapters are not standardized and may therefore be specific to the device they came with. Connecting them to a PS/2 port would require a protocol converter, actively translating between the protocols. Such adapters only support certain classes of USB devices such as keyboards and mice, but are not model- or vendor-specific.

Older PS/2-only peripherals can be connected to a USB port via an active converter, which generally provides a pair of PS/2 ports (which may be designated as one keyboard and one mouse, even though both ports may support both protocols) at the cost of one USB port on the host computer.[14]

Color code

Original PS/2 connectors were black or had the same color as the connecting cable (mainly white). Later the PC 97 standard introduced a color code: the keyboard port, and the plugs on compliant keyboards, were purple; mouse ports and plugs were green. (Some vendors initially used a different color code; Logitech used the color orange for the keyboard connector for a short period, but soon switched to purple.) Today this code is still used on most PCs. The pinouts of the connectors are the same, but most computers will not recognize devices connected to the wrong port.

Hardware issues

This section: Hardware issues needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "PS/2 port" – news · newspapers · books · scholar · JSTOR (March 2011) (Learn how and when to remove this template message)

This section is missing information about i8042 issues as described in Glasgow. Please expand the section to include this information. Further details may exist on the talk page. (December 2020)

Hotplugging

PS/2 ports are designed to connect the digital I/O lines of the microcontroller in the external device directly to the digital lines of the microcontroller on the motherboard. They are not designed to be hot swappable. Hot swapping PS/2 devices usually does not cause damage because more modern microcontrollers tend to have more robust I/O lines built into them which are harder to damage than those of older controllers;[15] however, hot swapping can still potentially cause damage on older machines, or machines with less robust port implementations.

If they are hot swapped, the devices must be similar enough that the driver running on the host system recognizes and can be used with the new device. Otherwise, the new device will not function properly. While this is seldom an issue with standard keyboard devices, the host system rarely recognizes the new device attached to the PS/2 mouse port. In practice most keyboards can be hot swapped but this should be avoided.

Durability

PS/2 connectors are not designed to be plugged in and out very often, which can lead to bent or broken pins. Additionally, PS/2 connectors only insert in one direction and must be rotated correctly before attempting connection. (If a user attempts to insert the connector in the wrong orientation and then tries to rotate it to the correct orientation without first pulling it out, then bent pins could result.)

Most but not all connectors include an arrow or flat section which is usually aligned to the right or top of the jack before being plugged in. The exact direction may vary on older or non-ATX computers and care should be taken to avoid damaged or bent pins when connecting devices. This issue is slightly alleviated in modern times with the advent of the PS/2-to-USB adapter: users can just leave a PS/2 connector plugged into the PS/2-to-USB adapter at all times and not risk damaging the pins this way. A USB-to-PS/2 adapter does not have this problem.

Fault isolation

In a standard implementation both PS/2 ports are usually controlled by a single microcontroller on the motherboard. This makes design and manufacturing extremely simple and cheap. However, a rare side effect of this design is that a malfunctioning device can cause the controller to become confused, resulting in both devices acting erratically. (A well designed and programmed controller will not behave in this way.) The resulting problems can be difficult to troubleshoot (e.g., a bad mouse can cause problems that appear to be the fault of the keyboard and vice versa).

See also

• BIOS interrupt call
• DIN connector on IBM PC keyboards
• Bus mouse
• Connections on mice
• DE-9 connector
• USB

References

1. ^ There is actually no technical reason that either port could not work with either type of device, if appropriate software was written to support that arrangement.
2. ^ a b "The PS/2 Mouse Interface". 1 April 2003. Archived from the original on 16 September 2008.
3. ^ Compare the logic diagrams in the IBM Personal Computer Technical Reference manual with those in the IBM Personal Computer AT Technical Reference manual.
4. ^ IBM Personal Computer Technical Reference, IBM Personal Computer AT Technical Reference
5. ^ IBM Personal Computer AT Technical Reference
6. ^ "PS/2 Keyboard (IBM Thinkpad) Y adapter". RU: Pinouts. Retrieved 14 June 2011.
7. ^ Lenerz, Gerhard (7 November 2006). "Common Input Devices". Hardware. SGIstuff. Archived from the original on 26 June 2007. Retrieved 14 March 2007.
8. ^ "Power Computing PowerBase". Low end Mac. Retrieved 4 April 2011.
9. ^ "Massive, undetectable security flaw found in USB: It's time to get your PS/2 keyboard out of the cupboard". ExtremeTech. Retrieved 26 October 2015.
10. ^ a b "Mouse Optimization Guide: Acceleration Fix and Polling Rate".
11. ^ "Computer Labs 2012/2013 - 1st Semester Lab 5: The PS/2 Mouse".
12. ^ "Device Class Definition for HID 1.11" (PDF). Archived from the original (PDF) on 11 August 2014.
13. ^ "N-key Rollover via PS/2 and USB". Geek hack. Archived from the original on 25 December 2010.
14. ^ "The pros and cons of PS-2 to USB adapters and converters". TechTarget.
15. ^ Adam Chapweske (5 September 2003). "The PS/2 Mouse/Keyboard Protocol". Archived from the original on 16 November 2016. Retrieved 26 November 2016.

External links

Wikimedia Commons has media related to PS/2 connector.

• "Keyboard and Auxiliary Device Controller" (PDF). Hardware Interface Technical Reference -Common Technical-. IBM. October 1990.
• PS/2 keyboard and mouse mini-DIN 6 connector pinouts, Burton sys.
• PS/2 In-depth information, Computer engineering, archived from the original on 1 September 2006, retrieved 11 September 2006.
• Technical information on Interfacing with the AT keyboard, Beyond logic, archived from the original on 30 August 2018, retrieved 25 March 2012.

Retrieved from "https://en.wikipedia.org/w/index.php?title=PS/2_port&oldid=1113010489"