A-Four tech Co.,LTD  company – (briefly A4TECH) a Taiwan producer of computer equipment was founded in 1987. Nowadays optical-mechanical manipulators of "mouse" type are the most well-known products of the company. Application of a new microcircuit of WWW–307 type controller and position-sensitive photoreceivers made it possible to increase their resolution capability and manipulator operation speed, as well as to provide the full set of additional functions. According to the results of some computer magazines the "mouse" of A4TECH сompany took in 1998 the first places regarding the quality-to-price ratio. At the CIS market the "mouse" of A4TECH appeared in 1990 and they operate until now.

Parameters of "mouse" type optical-mechanical manipulators.

1. Interface type of a supported device. Manipulators with Serial Mouse and PS/2-Mouse type interface are the most widely widespread. The Buse Mouse interface are practically gone out of use, but the USB interface has not yet received wide spread occurrence in spite of some advantages.
1.1. Serial Mouse type interface – manipulators with such interface are connected to COM1 or СOM2 communication port (RS-232) using DB-9 or DB-25 plug. There are special adapter connectors 9\25 and 25\9, which enable to connect the mouse to a vacant jack of the computer. The main advantage of such interface – a mouse can be connected to the computer without its turning off, i.e. "in hot condition". However, it is the slowest interface at the same time.
1.2. PS/2 Mouse type interface – manipulators with such interface appeared in PS/2 computers. At present, practically all modern motherboards support this interface. The main advantage of this interface – vacant COM1 and СOM2 ports, a mouse with PS/2 type interface provides 40 counts per second (60 – with Windows NT). There is possibility to increase the speed up to 200 counts per second. This parameter is important when using a manipulator in dynamic games. The only shortcoming is that a mouse cannot be connected and disconnected "in hot condition".
1.3. Mice with universal (Combo) interface – have the built-in controller, which enables to recognize an interface type automatically makes it possible to work both with RS232 interface and with PS/2 interface. Mice are supplied with passive adapter connectors to PS/2-RS232 jacks. Just these mice are the most preferable for a user, because they enable to carry out more flexibly the setting and modernization of a computer for certain tasks.
1.4. Mouse with USB type interface – the most high-performance mouse – 125 counts per second. It is possible to increase speed up to 200 counts per second. The mouse is connected to the computer in "hot condition". And you can connect totally up to 127 such devices to one computer only.

2. The number of buttons in a manipulator, including programmable buttons. As a rule, it is enough to have two buttons, however, mice with three, four and even five buttons have appeared, at that these additional buttons can be programmed to perform functions of keyboard keys. Frequently the mice of some producers have three buttons; however, the third button cannot be used due to the absence of software for it.

3. Scrolling wheels. For work convenience with multipage documents, some manipulators have one or two wheels for longitudinal and transversal image scrolling on the screen.

4. Resolution capability. The resolution capability D is determined by the number of slits N in the interrupter of light flux, radius of the interrupter roller in inches, slipping of the manipulator ball on the of roller surface k and the contamination level of the roller d. In the simplest case
D = 4*d*k*N*/2p*r, where: k=1/L L – mouse ball path, 1 – path of a point on the interrupter roller surface; d=r/r', where: r' is the radius of a dirty roller. Application of special treatment methods of available signals by the microcircuit of a mouse increases its resolution capability. The resolution capability of A4TECH mice is 520 d.p.i.

5. Resistance to light. Some mice cannot operate when the light is bright due to the ingress of intensive external light to the manipulator sensors. A4TECH mice do not have this shortcoming.

6. Contamination resistance. It depends on a mouse design, namely on the fitting tightness of the ball to the insertion of the case, ball material, axis diameter of the interrupter. A4TECH mice are structurally very steady to contaminations.

7. Mouse ergonomics. Everybody must select a mouse, which is the most comfortable to work with. A4TECH mice have four main form-factors of the mouse shape, which will be suitable for the hand of the most exacting user.

8. Cable length. Usually the cable length is 1.5 meter.

9. Price. As everyone is well aware, the price is often a determining factor when selecting an item. For informational purposes: the price of the first five best-selling models of "Mouse" type manipulators in the world was less than $20.

10. Package. There are three types of packages: Bulk, OEM and Shop. Bulk is the white cardboard package without any information. OEM is the colored package with minimum information about a product. Shop is the colored package with complete information and the User’s Manual and transparent windows through which a product is visible.

Comparison of specifications of simple "mouse" type manipulators of different producers

Comparison of specifications of “mouse” type manipulators with additional functions of different companies

Comparison of “mouse” type manipulators with the complete set of functions of different producers

How to handle a mouse?

· Do not contaminate a pad with cigarette ash, tea, coffee, candies or butter.
· Clean a pad with alcohol, if it is dirty.
· Regularly clean the mouse – its ball and modulator rollers.
· Avoid the mouse dropping from the table to the floor.
· Do not pull out PS/2 and universal mice from a jack during computer operation and do not connect it again.