Want to hook up my sister's computer (upstairs) to my Father's Lan (Linkysys router-cable modem) in my parent's house. Problem is: Their phone line is a dual line. Is this possible with the phone line networking kits? SInce I have no experience with these, how is the speed? I assume no problems using phone and sending/receiving data at same time. Dual line compatiblity is the main factor here. Thanks!