i am new to my company, my company use verizon phone service, and 1 of phone line is ISDN line, we use it do the video conference oversea. my company use Covad T1 service, my question is if Covad is down, can I use ISDN line to go to internet? do we need order service from verizon? if not, how can we go to internet with ISDN? Thanks

You would want to ask your isdn provider that question. Isdn is usually quite expensive especially when compared to dsl.

The situation is, as I understand it, the company already has and is using the ISDN line for specific company business. The question is, can the ISDN line also be used as a backup Internet connection in case the normal T1 connection goes down. The answer is yes. I used ISDN to connect to the Internet back before DSL was available. But, you will need an ISDN modem, and I'm not sure where you can find one. I still have the one I used years ago, but I don't know anyone selling them now. But, once you have the modem and you get it properly set up, then it's just a matter of having a dial-up account with an ISP which provides dial-up telephone connections, the "modem bank" equipment that ISPs use will usually support ISDN dial-ups. It's just like using an analog modem, but after the connection is made it is a pure digital connection and much faster. You can use a single line off the ISDN for 64kbps or bind the 2 for 128kbps. However, it may be difficult to find an ISP which supports the 128kbps connection.