I'm working to connect all five routers including 3 2501, 1 2507 and a 1720 and I'm able to connect the serial ports with cross over cables, and even the Ethernet ports, but need some help to connect my 1720 Wic cards. I have two 56K csudsu Wic cards and would love to connect them into my network but I don't know how and need some help on the best way to make this happen. I'm willing to buy different Wic cards if I need to. I need the experts to help me because I'm lost on this. Thanks for the step-by-step help on this.