Almost all new desktop and laptop computers come with Ethernet circuits directly on the motherboard, and laptops also have built-in Wi-Fi for wireless connectivity. To retrofit older desktops, network adapters can be plugged into the PCI bus, or USB-based adapters can be plugged into a USB port, eliminating the need to open the case. For older laptops, network adapters connect via a USB port or PC Card (CardBus) slot |