I have currently access to Internet provided via cable modem, with single Ethernet output port. From earlier, I have PENTAGRAM Cerberus P 6331-4A ADSL modem/router. Would it be possible, and how, to configure said ADSL router to serve just as a hub / switch, for sharing my Internet connection. I'm especially interested in using the WiFi part of it.

PENTAGRAM Cerberus P 6331-4A has built-in 10/100 Mbps 4-port switch for LAN, 1 x WAN port for ADSL-type connection, and Wi-Fi 802.11b/g. I want to conect cable modem to one of Ethernet ports, desktop PC to other Ethernet port, and use WiFi connection from laptop.