Do-it-yourself local network: Selecting a router (router) and its main characteristics. Connection interfaces - types and application What is a wired interface not available
COM port (Communications Port). Follow-up The interface uses one signal line to transmit data in one direction. Follow-up transmission allows you to reduce the number of signal lines and improve communication over long distances. This port provides asynchronous exchange using the RS-232C standard. A characteristic feature of the interface is the use of non-TTL signals - all external signals of the port are bipolar. There is no galvanic isolation - the circuit ground of the connected device is connected to the circuit ground of the computer. The transmission speed can reach 115.2 Kbps. Purpose - connecting communication equipment (for example, a modem) to communicate with other computers, networks and peripheral devices.
The RS-232C standard describes unbalanced transmitters and receivers - sig. transmitted relative to the common wire - circuit ground.
In asynchronous transmission, each byte is preceded by a start bit, followed by data bits and a parity bit, then a stop bit. . Bauds are used to measure the frequency of changes in the line status signal. "Current loop" is a common option serial interface. In it, the electrical signal is not the voltage level relative to the common wire, but the current in the two-wire line connecting the receiver and transmitter. A logical one corresponds to a current of 20 mA, and a logical zero corresponds to the absence of current.
25. Wireless communication interfaces. Infrared interface.
The use of emitters and receivers in the infrared (IR) range allows wireless communication between a pair of devices separated by several meters. Infrared communication - IR (InfraRed) Connection - is safe for health, does not create interference in the radio frequency range and ensures transmission confidentiality. IR rays do not pass through walls, so the reception area is limited to a small, easily controlled space.
There are infrared systems of low (up to 115.2 Kbps), medium (1.152 Mbps) and high (4 Mbps) speeds. Association of developers of infrared data transmission systems IrDA (Infrared Data Association), designed to ensure compatibility of equipment from different manufacturers. The current standard is IrDA 1.1. The emitter for IR communication is an LED with a peak power spectral characteristic of 880 nm; The LED produces a cone of effective radiation with an angle of about 30°. PIN diodes are used as a receiver, effectively receiving IR rays in a 15° cone. Interference: illumination from sunlight or incandescent lamps, which gives a constant component of optical power, and interference from fluorescent lamps, which gives a variable (but low-frequency) component. This interference has to be filtered. The IrDA specification provides a bit error rate (BER - Bit Error Ratio) of no more than 10~9 at a range of up to 1 m and daytime. Since the transmitter almost inevitably causes illumination of its own receiver, introducing it into saturation, it is necessary to resort to half-duplex communication with certain time gaps when changing the direction of exchange. To transmit signals, binary modulation is used (there is light - there is no light) and various coding schemes. For applied use of IrDA, in addition to the physical connection of the adapter and transceiver, installation and configuration of the appropriate drivers is required.
To understand what this article is about, you need to understand the meaning of the word “Interface”. This word means the possibilities, ways and methods of interaction between two systems. The router interface is its connection, communication with something.
In our case there are two interfaces:
- One system is a person (user), the second system is the router itself. That is, the user needs to go into the router settings and make some changes there to make it work according to their requirements. This is the settings interface.
- One system is a computer network, the second system is again the router itself. That is, it must communicate with a computer network (in fact, this is what it was created for); for this, the router must have a connection to the network either via wires (LAN, WAN ports, etc.) or via Wi-Fi. This is the connection interface.
Let's take a closer look at both interfaces, and start with the settings.
Router settings interface
As we already understood, in order to configure the router, we must enter into a dialogue with it. That is, we give him a command, he hears us, understands, and carries out. The interface, that is, the intermediary between the user and the router, will be the most common web browser (IE, Firefox, Opera, etc.). This happens as follows.
We connect the router to the computer using a network patch cord, or via Wi-Fi, and launch a web browser. Any router has a network IP address - enter it into the address bar of the browser. For example – 192.168.1.1.
Login to router settings
It’s not difficult to find out the address of your particular router - either turn it over and read the IP on the label under the bottom, or in the instructions for setting up the router.
The IP address of the router is on the label under the bottom
We press “Enter”, and the router will immediately ask - who do I have the honor of communicating with? That is, authorization is required. The username and password are also indicated under the bottom of the router and in the manual. Enter them in the appropriate fields and enter the settings menu.
Router settings
After entering the settings, direct communication with the router and its configuration begins. For convenience for a person (but not for a computer or router), settings are made in a convenient menu, with items and sub-items.
Router settings window
All this “understandability” and “logicalness” of the menu is only needed by a person, and it really works - setting up the router is very easy and quick, even for a user with little experience. This indicates a user-friendly interface.
For example, we need to configure Wi-Fi.
Setting up a Wi-Fi router
Of course, we go to the “Wireless” menu item, which means wireless network.
Settings Wi-Fi router
In the window that opens, we configure exactly Wi-Fi networks, nothing else. There is communication between the user and the router, mutual understanding, interface.
Network interface
Let's consider the second case of the interface, this time physical (previously it was interactive). Although at first glance there is nothing in common between them, there is one thing in common - this is the interface. Only in this case it is already a network one - the router is physically connected to computer network wires with special connectors (ports), or wireless connection, which in this case is not important.
Network interfaces of the router on the rear panel
The physical connection of computer network wires is made to these ports. There are at least two types of them - those “looking” at the outside world, that is, connecting to another network or provider (WAN port), and those “looking” at their own internal network (LAN ports). The Linux operating system even assigned names to these ports - the WAN port is designated “eth0”, and the LAN port is designated “eth1”.
Wired interface
For a wired connection, you will need a network cable. There are several varieties of them - twisted pair, coaxial cable and optical fiber.
Network Cable Types
Each type has its own connector for connection, that is, a coaxial cable cannot be connected to a twisted pair port.
The most commonly used type is twisted pair - the golden mean between price and data transfer speed. The cable is connected to the corresponding port of the router (network interface of the router), and the other end to network card computer (PC network interface).
Connecting to a computer
For different types conductor this procedure connections are no different, they are the same type.
Setting up WAN and LAN interfaces
Having connected the wires, let's move on to setting up the router. We familiarized ourselves with the procedure for logging into settings via the web interface at the beginning of the article. Having gone into the settings, go to the “Network” tab.
Setting up a wired network
By selecting a menu item, a submenu will open containing separate LAN and WAN port settings. We go to the appropriate subparagraphs and configure them in the way we need. Specific settings are not discussed in this article.
After entering the changes, be sure to click “Save” so that the changes are saved and activated.
Wireless interface
Wires are now becoming a thing of the past, and more and more is being devoted to the development of wireless interfaces. These include Bluetooth, infrared transmission and, of course, Wi-Fi. Wi-Fi is the future.
Through Wi-Fi, computers and routers are connected over the air using radio waves with a frequency of 2.4 GHz and 5 GHz (6 GHz is in development). Radio modules and antennas are required for communication.
Wi-Fi router
When you turn on your router, it creates a wireless network that your computer needs to discover and connect to. Wireless network has a name and, according to the rules of good manners, a password for connecting to it.
All found networks are displayed on the computer desktop in the lower right corner.
List of detected Wi-Fi networks
By double-clicking on the name of the network, we will connect to it. But first you need to configure it in the router settings. How to enter Wi-Fi settings was described in the first part of the article.
Finally, a video lesson on how to set a password on the interface of TP-Link routers:
Approximately three million users perfect quality images and accessibility are just part of the benefits IPTV television– services offered by Rostelecom. Meanwhile, technical support specialists often have to answer the question: why interactive television does not work on Rostelecom, despite the fact that there are no problems with the Internet connection. Despite the fact that RTK specialists are constantly improving the quality of their service, problems with IPTV do occur, and this is far from uncommon. If you have a situation similar to the one when Rostelecom television does not work, but the Internet works, do not fall into despair, since in most cases the problem is solved, even without the intervention of specialists.
No matter what the quality of the services provided, any technology can malfunction and, unfortunately, a perpetual motion machine has not yet been invented either. I would like to warn you in advance: if your Rostelecom television freezes, 50% of the time this can be fixed by rebooting the receiver. Fascinated by the variety of media content from IPTV, many users of IPTV set-top boxes do not turn them off from the power source for months, only switching them to standby mode (Stand-BY) before going to bed. Considering that the service is constantly being improved, and versions with new firmware appear, your equipment simply requires updating. In this case, disconnecting the router and set-top box from the network can help.
Among possible problems You can also select the connection of the TV tuner to the “wrong” LAN socket. Typically, the manufacturer allocates certain LAN ports to connect a TV set-top box, but if you decide to connect it through another port intended for an Internet connection, for example, nothing will happen. If you did everything correctly, but Rostelecom television does not show, you should look for the reason in a different direction.
Important! If you are using ADSL, you must use the LAN-4 port to connect; the same port is allocated when connecting via fiber optic. In the case of using two or three set-top boxes, the LAN-3 and LAN-2 ports are used, but never the LAN-1 port, intended for connecting the Internet.
You may encounter a message on your TV indicating that there is no signal from the set-top box. This happens quite often, and users ask why television from Rostelecom does not work when the Internet is working, if everything is done correctly and the receiver is connected according to the rules. In most cases, this happens because you did not indicate to the device the input through which the set-top box is connected, and modern television receivers provide several outputs for connection.
Error: no IP address
Among the most common reasons for the lack of signal, if Rostelecom shows a black screen, you should look for the reason in Wi-Fi settings router, although this may happen due to incorrect port settings by the provider. First of all, you must reboot the router and the set-top box, and if you have done this, and the television does not work, you can check the quality of the “twisted pair” connection - the cable leading to the set-top box. If the connections are tight, you should try connecting using a different cable - the problem may not be that there is no signal, but that the cable is simply worn out. The Rostelecom set-top box malfunction error can be corrected by changing the router settings, and this can be done at http://192.168.1.1, or by contacting support.
Endlessly running rabbit
Children really like the first turn on of some models of IPTV set-top boxes, as a rabbit appears on the screen, and then a cartoon “about hares” is shown. In fact, this is a problem related to the failure to receive firmware from Rostelecom via multicast. There may be two reasons for this:
- There was an error setting up the router, and in this case the set-top box may be assigned the wrong IP address. Setting the port for STB can help in this case, and do not forget to make sure that IGMP Snooping is enabled.
- Problems related to hardware configuration errors on the part of the service provider. This rarely happens, and only technical service employees can deal with the problem.
Important! If you think that the set-top box has stopped working due to a problem related to a router connection error (the port for connecting the STB is not configured), change the LAN port to a parallel WLAN port.
Incorrect login and password
A lot of trouble is caused by problems associated with authorization on the IPTV server or on the authorization server. You may enter, for example, an incorrect login or password. If you are sure that you entered everything correctly, but Rostelecom interactive TV does not work, you should refer to the settings of your router or modem. It may help, in particular, to check the router configuration settings and reboot the receiver itself. If IPTV from Rostelecom does not work, you should still contact technical support, whose specialists will check the authorization data.
No signal
If, after connecting the set-top box, there is no signal on the TV, as evidenced by the lack of image and sound, it may be necessary to configure the TV receiver itself. The point is that modern TVs different devices can be connected, so it is very important that the connection port matches the settings, since automatic mode Not all TV receivers have learned to do this. First, you need to find the Source button on the remote control, which is responsible for the signal source. By clicking on this button, you will be taken to a menu where you need to select the desired connection port. If you do everything correctly, the image good quality and a signal from Rostelecom will appear immediately. The problem may also be a loose connection of the contacts, and to fix it, just disconnect the cable and reconnect it. If you can’t solve the problem yourself, you won’t be able to do it without the help of a specialist.
loading error
Quite often, when users say that the Rostelecom TV set-top box does not work, they mean the message “Server not found” that appears on the screen. Below this inscription, users are advised to contact customer support. In fact, if the server is unavailable and Rostelecom does not show channels due to a server failure, you will not be able to solve the problem yourself. Help can only be provided by specialists whose help you will have to turn to.
Users of IPTV television can see an inscription on a black screen warning about a problem connecting to the server, while the system reports that the network interface is connected and an IP address has been obtained. This means that the Rostelecom server is unavailable due to a failure in the provider’s networks - a fairly common occurrence. In this case, leave the set-top box turned on and wait until the problem is resolved on the server. If the operation of the set-top box is not restored, it must be rebooted. First, the set-top box itself turns off, then the router; after turning on the router, 5-7 minutes should pass, after which you can turn on the receiver. The problem must be resolved.
Image in squares
If the image freezes, or Rostelecom television cannot be watched due to the appearance of a blurred picture with “squares”, and the sound does not disappear, but “stutters”, you need to reboot the set-top box again. If this measure does not help, or helps for a while, you can try disconnecting all devices from the router, with the exception of the TV tuner itself, and also try to turn off Wi-Fi. By gradually turning on all devices, you will determine the source of the channel’s download, and most often this happens on ADSL lines, and especially in cases where the channel is busy with downloads from file hosting services.
Wired interface not available
If you see a message about no wired interface, remember that the problem is a problem with your Internet line. Most likely, it can help solve it standard procedure reboot the router and receiver. You should also not forget about possible mechanical damage to the cable. You can check why the network interface is not connected by connecting a new cable.
Service (login) blocked
If Rostelecom channels are not shown, this may also mean that the service (login) is blocked. Timely payment for interactive television services can solve the problem, and you can check the status of your account in your personal account on the Rostelecom website; in some cases, replacing the set-top box helps.
Part I. Mice
Despite the fact that most of our readers are well versed in computer technology, it seems that there is a need for such a general educational series of articles. The fact is that in the high-tech field, like no other, the rate of introduction of new technologies is extremely high. So high that today's developments often peacefully coexist with yesterday's and even the day before yesterday's. As a result, there are simultaneously many options for peripheral devices on the market with a wide variety of interfaces. How do they differ from each other, what follows from this, what pitfalls can a user expect? Even specialists can get confused, not to mention those who just bought a computer not long ago and now want to change something in it (or on the contrary change the computer itself, leaving the already purchased peripheral devices alone). Reviews of specific equipment are not the best place to discuss the differences, so usually we just write that a device has one or another interface, without going into details. Well, now we’ll deal with them. Let's start with mice, since this equipment does not change very often, and this segment of the market is the most messy.
One general note from the very beginning: a clear distinction should be made between the connection interface and the data transfer interface. In the case of wired devices, this nuance can be neglected - the mouse, keyboard or other equipment is rigidly connected with a cable to the corresponding port. For wireless peripherals, the connection interfaces remain the same - PS/2, COM, LPT, USB, and so on, but only the receiver is connected to the port, and the mouse itself exchanges data with it using a radio channel or infrared rays. Closely related to this myth first:
Wireless devices are significantly different from wired ones.
In fact, this is not true. Regardless of the specific data interface, a mouse connected to a PS/2 port (directly or through a receiver) for a computer is a “PS/2 Mouse”. The computer makes no difference between them at all when using “simple” receivers. The situation is different in the case of Bluetooth, but precisely because in this case it is not a passive receiver that is used, but a Bluetooth adapter and itself peripheral device uses Bluetooth specifically as a connection interface (i.e. the scheme here is completely different than in the case of simple wireless devices). In all other cases, everything is simple, despite the fact that I have already heard once that “wireless mice do not work in DOS.” All wrong! If your operating system supports a serial, PS/2 or USB mouse at all, then it will work just as well with a wireless model whose receiver is connected to the corresponding port. And the characteristics of a wireless mouse will be the same as in the case of a wired one (of course, those for which the data transfer interface will not be a limiting factor). The same applies to keyboards, joysticks, steering wheels, printers and other external equipment.
Well, now that we have dealt with the rudiments of general mythology, let’s move directly to mice. We will consider interfaces in chronological order.
Parallel (bus) mice
It just so happened historically that the IBM PC was initially aimed at use in business, not entertainment (it’s hard to believe now :)). As a result, the main interface was text, and mice were simply not needed: there are only two (or even one) thousand “dots” on the screen, each of which can be easily and accurately accessed using the keyboard. However, the computer quickly acquired graphic functions, and here the keyboard began to give in: even in the now ridiculous-looking resolution of 320 x 200 pixels, the screen already contains 64 thousand addressable positions, so if you need to be able to easily get to any of them, use the keyboard You can't get by with keys. And software manufacturers realized that graphics are useful not only in games or graphic editors: if attached to a regular program GUI, it will not work faster, but for mastering by an untrained user it is better suited than a text one. Well, even now the best way to work in graphical environments is a mouse that was specially designed for this purpose, but in those days there was no choice at all: either a mouse or a light pen, which has much less accuracy than even the first mice.
But bad luck: the PC does not have a special mouse port! No one initially thought that it would be needed, since at first the most popular was MDA, which did not support graphics in principle. An interface for a light pen was provided, but there were too few people willing to use it (and no wonder: hold your hand suspended in front of the screen all day - by the evening it will simply fall off), but not for a mouse. At the same time, in all computers that were originally oriented towards graphical environments, the ability to connect a mouse was present from the very beginning. Well, the IBM PC architecture is open, bus, standard bus (later known as ISA), we will expand the capabilities. Some manufacturers (in particular, Microsoft) have mastered the production of mouse adapters, sold complete with mice, and installed in a regular eight-bit slot on system board. It would seem that the problem is solved.
However, tire mice did not live long enough and were quickly replaced by other options. As far as I know, these rodents did not manage to reach our region in any noticeable quantities, and in the Bourgeoisie in the second half of the 80s they disappeared as a species. There were two serious reasons for this. Firstly, the price: any mouse that uses a standard computer interface costs less than a set of a mouse and a special adapter - axiom. Secondly, expansion slots have always been a rather scarce resource. True, there were as many as eight of them on the original AT board, but in those days there were much more devices willing to occupy them, since there were practically no integrated components. So tire mice became extinct as soon as an alternative appeared.
Serial mice
Back in those shaggy years, someone (who was the first - it is now almost impossible to find out) came up with a great idea. Almost every computer is equipped with at least one serial port, which can be used to connect almost any equipment. Why can't it be a mouse? No sooner said than done. And serial mice flooded onto the market, which do not require additional controllers for their operation: a free COM port is all they need. The solution turned out to be, firstly, cheap, and secondly, very universal, since it was suitable even for computers that do not have expansion ports at all (portables, for example). It is not surprising that these models soon became the de facto standard.
Since the active invasion of rodents on the market began after the appearance of the AT, most models used a compact (at that time today it is the largest suitable for mice) nine-pin serial port connector, which was the standard for these computers. Models with a 25-pin connector were also found, despite the fact that it was too large, and both connectors were almost completely compatible, and mechanical incompatibility was easily resolved with the help of a passive adapter. The latter, apparently, led to the fact that already in the early 90s, mice with a “large” connector practically disappeared. Serial mice are extremely unpretentious; in particular, the port is easy to “hot plug”, they have a low cost, and for a long time their characteristics were more than enough for all users. It’s not surprising that many of us started working on computers equipped with just such mice, and with their help we mastered the first versions of window systems for PCs. Moreover, such mice can still be found, although many companies no longer produce them, and others have significantly reduced their share (for example, Genius has no more than 10% of the total, and Microsoft and Logitech do not make serial mice at all). In 2000, such a mouse could still be easily bought, but now just going to the market is not enough: serial mice from Genius, A4 Tech and some other companies are sold out quite quickly, due to the fact that in many places relatively old computers are still working, quite coping with their tasks, but unable to work with new mice. And it’s quite possible to find mice with a serial interface that were released a long time ago, which is largely due to the fact that in those years not only were the trees big, but the technology was more reliable. I still have in my closet a perfectly working serial mouse, MS Mouse 2.0, manufactured and purchased back in 1995, and you can connect it to your computer and use it at any time! However, this device then cost $35, despite its extreme primitiveness (today you can buy a good wireless optical mouse for that money), and cheaper models died out quite quickly.
So, for many years, sequential mice became the de facto standard. In fact, they began to lose ground even a little earlier than they became morally obsolete, only because specialized mouse ports appeared in computers, and the corresponding mice began to cost almost cheaper with a wider selection. Well, by this time some of the shortcomings of sequential mice had already become noticeable, which we will talk about below, which only accelerated the process.
PS/2 compatible mice
Back in 1987, when starting the release of the PS/2 line, IBM took into account all past mistakes. Unfortunately, it created new ones, so this architecture, revolutionary at that time, vegetated ingloriously for several years until it finally died. But its proud name still lives on this is the name of the mini-DIN ports for keyboards and mice, which were launched by this line. Yes, these computers now have a special mouse port, and even mouse support in the BIOS (both regular and ABIOS). It’s not surprising: these computers were initially designed to work under graphics control. operating system(according to IBM and Microsoft, it should have become OS/2), so the mouse began to turn from an optional device into a standard one.
It should be noted that the new ports had both advantages over serial (in particular, a lower supply voltage 5 V instead of 12 V, and independence from other devices, while serial mice often interfered with internal modems, since four COM ports The PCs were shared by only two IRQs), and there were disadvantages. The most significant is the “dislike” of connecting and disconnecting the mouse while the computer is running. Many people neglect this requirement, but only until the first burned port :) The probability of its burning out is far from 100%, but it exists, so it’s better not to risk it (at least it seems so to me). But they were, and they were used by one of the largest computer manufacturers. It’s not surprising that mice with the appropriate connector appeared, and manufacturers of brand-name equipment also adopted this standard, and began outfitting their computers with PS/2-style ports and a mouse controller. But the producers, already strong by that time, motherboards from Southeast Asia did not really want to increase the price of their products, so self-assembly and second-tier equipment, which always had more than brands, continued to make do with successive mice. However, somewhere in the mid-90s, the most respected companies from Taiwan began installing mouse ports on boards, but... I had a port on the ASUS PVI-486SP3, but in order to bring it out, an optional bracket was required. Three dollars, of course, is not money, but why? To buy a PS/2 instead of a serial mouse for the same money? If both serial ports were occupied, I would have done this, but most (including me) had at most one modem, and some did not even have one. So they lived PS/2 mice captured about a third or a quarter of the market, consistent everything else.
The stable balance was disrupted around 1997. While developing the ATX standard, Intel company, of course, took into account the necessity of a mouse, so that a PS/2 port became a mandatory accessory for every computer that aspires to modernity. Well, if everyone has a port, then why not use it? AT format motherboards, however, disappeared from the market slowly, but even in their case, the “miscarriage” with the port became a mandatory component. Thus, PS/2 mice quickly became the standard.
USB mice
However, having given the green light to PS/2, Intel quickly tried to turn the process onto new tracks. The PC98 specifications recommended connecting the mouse to USB port, in PC99 it was strongly recommended to do this, although it was not forbidden to use PS/2, but COM ports were already advised to be removed. In PC2002, an unambiguous command was generally given for USB-only peripherals. However, it was not possible to quickly supplant PS/2; most motherboards still have ports, so why take up a USB port that can be used for other purposes? Moreover, at first, USB models were noticeably more expensive (and there is still some difference in their cost, although it is already small enough to be invisible to the end buyer).
So the progress of USB mice to the market has been quite slow. However, it is very easy to ensure compatibility between USB and PS/2, since both buses are designed for 5 V power supply, so, slowly but surely, USB mice began to gain a place in the sun: it turned out that it was not at all necessary to release models designed only for one interface for almost the same money you can support both. The first to “give up” were boxed mice, especially those models whose release as an OEM version was not planned: they are not cheap in any case, so two or three dozen cents for an adapter compared to two or three (or even five or six) tens dollars won't make a difference. For OEM, some companies have chosen USB as the main standard, and an adapter (those who need it) can purchase it themselves. However, since even now most mice are made on the basis of the same controllers, with some design complexity to support USB, a considerable number of “middle class” mice continue to be produced in the PS/2 version (many manufacturers have the majority), well models focused on budget segment, in general, they haven’t started switching to USB yet. As special mouse controllers with USB-only support become more widespread, this interface will gain more and more positions, and over time, the PS/2 port can be removed painlessly and no one will notice anything.
By the way, about old equipment and, accordingly, about old programs. Has been around for a long time myth two:
USB mice do not work in DOS, Windows 95 and NT4.
Generally speaking, at first this myth had a basis in reality - they really didn’t work. However, three years ago, BIOS manufacturers became concerned about the problem, so BIOS support for USB mice appeared in outdated operating systems (keyboards learned to do this a little later). So, even though the boxes with mice indicate that a minimum of Windows 98 or 2000 is required when connecting to USB, you can use an older system. True, you will lose the scroll wheel, since it is not supported by built-in tools, and you will not be able to install native drivers (which, by the way, means that some mice cannot be used at all; without additional software, many models do not work at all, even as two-button mice). However, old Windows versions are interesting only for academic purposes, but sometimes you need DOS boot from a floppy disk and play an old game, for example :) There is no need to rush to look for an adapter when using modern motherboards A USB mouse will work as expected.
Bluetooth mice
They appeared quite recently both by historical and computer standards. But I'm already connected to them myth three:
Mice with a Bluetooth interface are analogues of conventional wireless models with a radio or IR interface.
In fact, this is nothing more than a myth Bluetooth is not a data exchange interface, but a connection interface. What is misleading is that now such models are usually equipped with Bluetooth adapters, just like regular wireless models are supplied with receivers. In addition, for example, the Logitech MX900 at first glance is no different from the MX700: the mouse is the same in appearance, the same base, only Bluetooth is used, which, in fact, is the same radio connection (the frequency is different, but many models also operate at 2.4 GHz radio mice). However, the adapter is not at all an ordinary wired-to-wireless converter. This is really an adapter that gives your computer the ability to work with Bluetooth devices. And one of them (if there is an appropriate profile) can be a mouse. Theoretically, these models can work with adapters other than those included in the package, and they themselves “do not know” what kind of adapter is used: built-in, on PCI bus or the most common USB. And even in the latter case, there is no point in drawing parallels with wireless mice whose receivers are connected to a USB port this absolutely different devices . Bluetooth mice are a separate class of equipment. It’s still exotic, so we still have to deal with them and deal with them. But, most importantly, the main material of this article does not apply to them. There are problems with their functioning under DOS, since they require an OS that has drivers for the Bluetooth adapter. Well, our further story will not concern them we will talk about the operating features of the more familiar mice with serial, PS/2 and USB interfaces (as I said at the beginning, everything will be equally true for both wired and wireless models).
Polling frequency
In general, mice do not have many objective parameters expressed in numerical form, and polling frequency is just one of them. The higher this value, the better. Maximum polling rate port depends on its type, the operating system used and some utilities that can improve it. To begin with, the actual information is in one table.
Question marks in the case of a serial interface indicate that I don’t have accurate information, since I don’t know the users of XP and a serial mouse, I don’t want to measure it myself, since no one seems to need it, and it’s still impossible to find out the maximum possible value, since manually in his case, the polling frequency cannot be adjusted. In the case of USB, manual adjustment when using Windows is also impossible (at least, the methods for doing it are still unknown), but the polling frequency is always quite good. And the most interesting situation is in the case of the PS/2 port disgusting results under 9x, gradually improving as the OS improves, but not reaching USB, and as much as 200 Hz maximum (one and a half times higher than for USB!) with manual adjustment. The latter is done quite simply: regular means in XP (since there were many questions about this, I’ll say where: in the list of devices, select the mouse, and then advanced properties), through the registry in 2000 or using special programs(like PS2 Rate Ajuster) under 9x (I don’t know how it is in NT4, but this system is not used for games, so it’s not very important). Why do we even need a high polling rate? I will quote a paragraph from an old article:
Let us play Quake II on an 800x600 screen. We assume that we see 120 degrees, then the full circle will be 2400 pixels. If we need to rotate 180 degrees in one second, then the rotation will be 1200 pixels. In this case, a PS/2 mouse will give 40 counts by default. Then it turns out 30 pixels per sample, i.e. by turning, we can shoot with an accuracy of 30 pixels. If we are playing deadmatch and our opponent is far away, then this simply will not be enough!
The article was published on our website more than four years ago, but since then the situation has become even worse as the permissions used have increased. 1600x1200 is still exotic, but 1280 is quite common, so we will assume that there are already 1800 points in the rotation. Then at the same 40 Hz (PS/2 or COM at 9x) we will get an accuracy of 45 pixels. It’s difficult to call this exact; in fact, you will hit the white light like a penny, and the enemy will die only if he himself constantly tries to get under your shots. A Windows 2000 user will already get 30 pixels as stated above, not enough. Under XP the result is better 18 pixels. A USB mouse will always provide approximately 15-16, and an overclocked PS/2 as much as 9 pixels. In the latter case, it is unlikely that anyone will leave your tenacious clutches alive.
But this can get a little confusing. Since PS/2 provides the highest frequency, why do we need USB? Here it is for you myth four:
For gaming, you definitely need a mouse with a PS/2 interface; it will guarantee the best results.
The fact is that we considered the port polling frequency above. However, the mouse itself may not be able to output data at that speed. And it turns out that a “bad” PS/2 mouse will really only give you about 80 Hz (old wireless models generally didn’t reach more than 50 Hz), while a “good” USB will honestly work out its 125 Hz. If the mouse has a polling frequency of only 100 Hz, then it doesn’t matter which port it is connected to, and you don’t even need to overclock PS/2 for XP. Although the best (from a gaming point of view) PS/2 mice do indeed maintain the required 200 Hz or so, and allow you to get maximum accuracy in the game, you should not make this a rule. In real conditions, it most often comes down to the mouse, although PS/2 has greater potential, which is always worth remembering.
At least this is true for Windows. Linux users can significantly overclock the USB port. Here's what one of our readers wrote:
If you use a USB mouse, you can get up to 1000Hz in Linux OS using special kernel patches. The patches can be found here: I tried to install the patch for the 2.4.22 kernel, M$ IE explorer 3.0a and Logitech M-BA47 produced 500Hz. There in the source code one line needs to be changed and it will be 1000Hz.
I don't use Linux myself, so I can't check. But I think this information will be useful to many.
Interface compatibility
Since it just so happened that for a long time at least two interfaces were widespread on the market (in fact, even three, but at first USB was rare, and now COM), the question is: “What can I plug into what?” sometimes he gets up. And how many disputes there are about it in different conferences :) Let’s try to give an exact answer to it - someone has to do it in the end, and if not us, then who? :)
We will move in chronological order. A serial mouse connects only to the serial port. The most common are 9-pin directly or 25-pin via a passive adapter, rare models with a “large connector” vice versa. All. Nowhere else in most cases. Not even in USB, despite the existence of USB-COM adapters. The fact is that, as I already said, a serial mouse needs a 12 V power supply, and the USB port and the mentioned adapter, respectively, output only 5 V. Modems or other devices with external power do not experience any problems from this, but mice most likely, they will not work (which is what many encountered immediately after the appearance of these adapters. However, there are also opposite examples some mice (mostly recently released ones) with some adapters work, but this is the exception rather than the rule.
Mice with a PS/2 interface can, of course, be easily connected to the appropriate port. To connect them to USB, there are special active adapters useful considering that most modern laptops and some desktop computers They no longer have PS/2 ports. There are no problems with power supply in this case (both 5 V), however, you should keep in mind that this adapter will turn your mouse and keyboard (if you connect it too) into standard USB devices with all that it implies in particular, if devices come with special software, then it will not work when using an adapter. In general, it is impossible to connect a PS/2 mouse to a serial port, but at one time there were quite popular models that supported both standards. By default, they had a PS/2 connector and an included adapter, with which they were plugged into a 9-pin COM port. However, not all mice are able to behave this way, and they have not been produced for a long time. So don’t expect that a newly purchased PS/2 mouse can be easily connected to a serial port using an adapter purchased on the market; it is only suitable for initially dual-standard mice.
As for USB mice, they easily and naturally connect both to their own connector and, using a passive adapter, to PS/2. And so far the vast majority even those for which this is not stated and there is no adapter included :) The point is the identity of the controllers, which I already wrote about above, which is why to turn a USB mouse into a PS/2 a penny adapter is enough, according to at least for now. On the other hand, there are already a number of USB mice based on the new element base, but they cannot be plugged into the PS/2 connector. It is difficult to say in advance whether something will work out or not. However, if you know for sure that this mouse found in a boxed version along with an adapter included, or this model has a twin with a PS/2 connector (most often called the same), then you can be 99% sure that the trick will be successful.
Closely connected with adapters myth five:
A USB mouse via a USB-PS/2 adapter is not a PS/2 mouse at all, but something in between.
In fact, it’s nonsense: no matter how you received the PS/2 connector: it was originally on a cable or obtained using an adapter from USB the result will be absolutely the same. The only thing is that this design will have a slightly worse hold, so you shouldn’t pull the cable too hard: you should forget about hot plugging. And other properties are similar to PS/2, and are not inherited from USB. In particular, it is incorrect myth six:
There is no point in overclocking the PS/2 port when connecting a USB mouse to it via an adapter, since the actual polling frequency will not rise above 125 Hz anyway.
You don’t even have to comment; it’s just a myth. Those who have checked know that many models are overclocked to almost 200 Hz, despite the fact that they seem to be “virgin” (in terms of the connector) USB.
The last unanswered question is whether it is possible to connect a USB mouse to a serial port (which, by the way, some people are trying to do). If you carefully read the last two parts, you yourself will be able to explain to someone why this is impossible.
Well, now a small plate to secure the material. Columns mice, rows corresponding ports.
Total
Well, we studied the history of mice and mouse interfaces, debunked six myths that can ruin your life, and discussed some aspects of using mice. I hope that the information provided is useful to you. And in the next part we will deal with keyboards.
