I have been testing 2610 and 2611 routers (The only connection is through console port and ethernet to the TFTP server).i have not connected the ISDN, ASDL or SERIAL INTERFACES with any cable. The routers recognize all the Ethernet and WAN interfaces. The ethernet LED is OK but the WAN cards LED are off. I have configured the interfaces of these WAN cards(A BRI, ISDN and SERIAL interfaces) with IP address, when i use the command Show interface i can see all the interfaces are UP and line protocol is UP. Is this enough to testify that the WAN interfaces are GOOD or is there any other technical way to test these interfaces. Does it need to connect all these WAN cards and PING them or is there a command which will be enough to prove that the WAN interfaces are all GOOD and not FAULTY. Can i use loopback command without using cables to test these interfaces? Please i need your help.