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drajanikanth

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Mouse

What is a PS/2 mouse?What is a serial mouse?
Are there any other mouse categories?What is the difference between them?How to distinguish between them
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pjknibbs

A serial mouse plugs into the normal serial ports on the back of a machine. It therefore has a normal serial connector which has 9 pins arranged in two rows, one row of 5 and one of 4. (It looks like a smaller version of the VGA monitor connector).

A PS/2 mouse plugs into a special mouse port on the back of the machine. The connector is round; it has 4 metal pins and a plastic "key" to make sure it goes in the right way round. Modern keyboard connectors are the same.

There are other ways to connect a mouse--you can get infrared ones that work in a similar way to your TV remote control--but these two are the major ones. Since *all* modern motherboards include PS/2 support (not all older ones did), the serial mouse is gradually dying out.
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ASKER

How can a serial port have 9 pins.A Serial port is one which employs serial comminucation.So one pin is sufficient.
What does it matter how many pins a serial communication *needs*? A standard PC serial port has 9 pins. According to my documentation the usage of those 9 pins is as follows:

1) Carrier Detect
2) Recieve Data
3) Transmit Data
4) Data Terminal Ready
5) Ground
6) Data Set Ready
7) Request to Send
8) Clear to Send
9) Ring Indicator

The separate Receive and Transmit pins allow for full duplex operation (transmit at same time as receive). The others are mostly "handshaking" pins which control the connection between the two ends.

Oh, by the way, I made a mistake with my description of the PS/2 mouse connector: this connector has six pins, not four, assigned as follows:

1) Data
2) Reserved
3) Ground
4) +5V DC
5) Clock
6) Reserved

Enough information for you now?
Oh, and your statement a serial connection needs only 1 pin is only true if both ends of the connection are earthed--in the case of a mouse or keyboard you'd always need at least two.
Thank you very much for your answer.By the way how does the PS/2 mouse communicate i.e. either in serial manner or parrell manner
Serial. As far as I know there's no such thing as a parallel mouse--it doesn't really transfer enough data to make it worthwhile.
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Some serial ports have 25 pins.  The first serial ports were 25 pin connections which was a standard definition - (possible the RS 232 defintion).  Later on IBM cut the connection size down to the 9 pin size which we have now because all of the pins weren't being used.

Other types of mice.  

There are USB mice as well.

You could talk about trackballs which are upside down mice.

Joystick mice and touchpads are both forms of mice and found in portables.
What are the differences and advantages of PS/2 mouse over serial mouse?
What are the differences and advantages of PS/2 mouse over serial mouse?
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pjknibbs

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Thank you very much for your answer and for spending your valuable time for me.