I have a router with one ethernet port and one usb port. but i don't use that usb port. I use a ethernet switch to connect my 2 computers and the router. I can share data between 2 PC without any problem. but the problem is i can't use broadband in both pc simultaneously, when one PC is using broadband then in other PC when I'm connecting broadband it says that the router is busy and then shows error 678. please help me to use broadband in those PC simultaneously.