What device enables internet access for two or more devices in a customer’s premises?

A router with a built-in multi-jack Ethernet splitter is the correct choice because it serves the essential function of managing and directing internet traffic within a network, allowing multiple devices within a customer's premises to access the internet simultaneously.

The router connects to the internet via a modem and then provides a local network for devices such as computers, smartphones, tablets, and smart home devices to connect either wirelessly (via Wi-Fi) or through Ethernet cables. The built-in multi-jack Ethernet splitter feature allows wired connections for multiple devices directly into the router, which enhances connectivity and speeds for devices that are hardwired, while also providing the functionality for wireless devices to connect over WiFi.

This is distinct from a standalone modem, which typically connects only one device directly to the internet. While devices like digital signal amplifiers can enhance signal strength for existing connections, they do not enable internet access for multiple devices. Thus, the router is the essential device that allows the distribution of internet service effectively within a location.