How do you connet to other system using port?

You can connect computers through various type of ports (e.g. through Ethernet (wired or wireless) , USB or Serial port. What port you pick, will depend on your application needs and at what speed you want the connection to work.

If two computers have 10/100Base-T Ethernet port these can be directly connected using a crossed Ethernet cable without need of a switch or hub. - Neeraj Sharma