Yes, in Windows XP Plug and Play was first introduced to allow devices such as the USB to be plugged in while powered on.
Hot swappable
The ability that allows USB devices to be plugged and unplugged with the power on is called hot-pluggable. The ability to use new devices without going through any type of configuration is called plug and play.
Yes, they can.
Depending on what you have plugged in, and what type of computer you have, the USB ports in your computer can "go to sleep", causing the recognition noise to sound as the ports go to sleep. For example, if you have a laptop and the battery gets too low, it will shut off some USB ports, and if you have a device or USB drive plugged in at the time, it will act as if you unplugged it from the computer, causing the noise to sound. The sound may also occur when devices turn themselves off. For instance, many computer printers like to stay off when they are not being used. The PC can wake them up when necessary, and when they turn off, Windows detects this, just as if they were unplugged from the computer.
I/O ports, short for Input/Output ports, are physical interfaces on a computer or device that allow the exchange of data with external devices. These ports can be used for connecting peripherals such as keyboards, mice, printers, and storage devices to a computer. There are different types of I/O ports, including USB, HDMI, Ethernet, and audio ports.
We can't say the ports are input devices. Ports are just interface to which provides communication medium to the devices.
USB and PS2
A firewall is what opens ports to allow devices, apps or anything to transmit anything
Peripheral ports such as COM, USB and serial ports, are input/output interfaces that allow devices to connect to a computer. Expansion slots are sockets on the motherboard where an expansion card is inserted.
modem
You can connect devices such as printers, scanners, mice, or many other gadgets that may not have room in the USB ports already designed into your laptop. This saves the devices being individually plugged into your laptop saving time and a lot of hassle.
An Ethernet Hub allows the user to hook up to four ports at one time. The Hub will allow you to connect multiple devices and allow them to act as one.