You can use the device as broadband router or a wireless hub/switch, connected via Ethernet cable to your Sky router. (you can't use it as modem/router with Sky)
Setup 1 (Broadband router setup, please note clients connected to the device in this mode will run behind double NAT)
1. Make sure you have firmware 6.24c loaded (http://www.billion.uk.com/esupport/inde ... c-firmware
2. Click on 'WAN' on the left hand side
3. Change the 'Profile Port' to 'EWAN'
4. Change the 'WAN Type' to 'Obtain a IP Address Automatically'
5. Click on 'Apply'
6. If your Sky router is within the same subnet eg 192.168.1.x = Sky router, 192.168.1.x = Billion you need to change the LAN IP address of the Billion router to 192.168.2.x (screen shot example attached)
7. Once done plug a Ethernet cable from the Sky router to Ethernet port 1 on the 7402GX. (please note the throughput speeds will be limited to around 40mbps, as this is a software emulated EWAN port)
Setup 2 (Wireless hub/switch, all routing, DHCP requests etc will be performed by your Sky router, so no double NAT)
1. Login to the router
2. Click on 'Advanced >> Configuration >> DHCP Server'
3. Disable the 'DHCP Sever Mode' and click on 'Next' and the confirm you want to disable the DHCP server
4. Plug a Ethernet cable from you Sky router to any of the LAN ports on the 7402GX
5. Restart any devices connected to the 7402GX.