PROBLEM RESOLVED.. I Faced The same problem after upgrading the firmware from motive.bsnl.co.in ,, AFTER The upgrade my inter didnot connect & gave me the error 678.. What u need to do is type 192.168.1.1 in the address bar of your browser & press enterit will ask for username & password1.Type ADMIN as username & password2. On the left hand side click on Configuration & then Internet3. Click on the Edit option of PPPoE_0_35 & next window which pops up change the value of VBI to 0 & VCI to 35 & service category to UBR with PCR & click on next4. In the Next window choose Protocol as Bridging & Encapsulation Mode to LLC/SNAP & click on next5. Skip Configure WAN IP Settings & click Next6. Click on Apply & it will take 90 seconds to change the settings & you are doneDont forget to pass on the comments if it helpsThanks Umar