Dial-up networking error 678

If you get "error 678" when trying to connect and you have ISDN, you must make sure you have the correct details within the connection:

1. Double left click on "My computer".

2. Double left click on "Dial-up Networking".

3. Single right click on the dialup connection icon and select Properties.

4. In the Properties window there is a "Connect using:" box. In the white area you need to make sure the correct protocol is selected. This protocol will refer to the make and model of your ISDN card, but must also mention "ISDN/PPP" for example: "US Robotics ISDN/PPP V2.5".  

Other ones that may be selected if available are: "channel 0" and "channel 1". If you don't have the option to choose any of these you may have to reinstall the drivers of the ISDN card so that you are able to choose one of these protocols in the "Connect using" box. It may also be that you have outdated drivers, in which case you will need to download the latest drivers for that particular card form the relevant manufacturer.