Final answer:
The connector used in computer systems for networks is an Ethernet port, used with an RJ45 Ethernet cable to connect to modems, routers, or LAN.
Step-by-step explanation:
The connector commonly used in a computer system to provide a direct connection to a cable modem, router, or local area network (LAN) is known as an Ethernet port, which uses an Ethernet cable. This cable is RJ45, a standard type of connector for network cabling. It allows devices to communicate with each other by transmitting data over the network. Most computers, laptops, and networking devices come with one or more of these ports to enable wired networking connections.