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When I connect a USB mouse to a working system, it will work fine but serial mouse isn't recognized by the system? To get the serial mouse working, I need to restart the system. Why is this?

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As pointed out by Dennis in comments below, the premise of the question is not necessarily true: one does not need to restart the system. – JdeBP Dec 19 '11 at 18:47
Serial (RS232) ports are technically not hot-pluggable (from the electrical/mechanical standpoint). So, you could fry older computer's serial ports while connecting/disconnecting serial equipment. So while the answers below give you options how to detect newly connected serial mouse, it is still better to connect it while computer is powered down. – haimg Dec 19 '11 at 20:53
up vote 4 down vote accepted

If I understand correctly, you want to know why USB connections don't need a reboot and serial connections do.

It might have changed, but as I recall, USB ports are always monitored, so if you add something, it automatically get recognized. Serial ports are only checked at boot time. So if there's nothing connected, then your PC won't try checking that port again.

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This. Old fashioned serial is not plug-and-play. It predates even the very concept by a long, long time. A better question might be why are you even still using a serial mouse? Where the hell can you even GET one these days? – Shinrai Dec 19 '11 at 17:34
@Shinrai I had an english teacher two years ago who hated optical mice. He could only use trackball mice. – wizlog Dec 19 '11 at 17:40
You actually do not have to restart the computer. It suffices to search manually for new hardware. To do this, enter the Device manager, click Action -> Scan for hardware changes. – Dennis Dec 19 '11 at 17:56
Correct, that "forces" a new search on all ports. – Teknophilia Dec 19 '11 at 17:59
@wizlog - I'd be surprised even if you could buy serial trackballs. (There are plenty of USB ones these days) – Shinrai Dec 19 '11 at 18:03

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