I am trying to setup a Cisco Lab to study for my CCNA exam. Currently I have a Cisco 2600 and 1720 series router, Cisco Catalyst 2950 and a Cisco Pix 501 firewall. I want to setup a WAN connection between the Cisco 2600 and the 1720 routers, but both routers have a T1 CSU/DSU card. Is it possible to emulate a WAN connection using T1 CSU/DSU serial ports or do I need to purchase a DTE/DCE serial port with cable? If so, can a 1720 router take a DTE/DCE serial port? What is the model number for the DTE/DCE serial ports for each of the routers? Also, if you have any suggestion on the best way to setup the lab to help with my studies that would be greatly appreciated.