Is that why and ISDN line gives you such a nasty shock when stripping it with your teeth?
Were you giving it the tongue-test? ISDN has a higher current capacity than a telephone line, as the router is not an inductance device.
btw: Lots of dodgy advice in these posts. Why does the OP not just call Telkom and get someone who knows what he is doing? If you have some electronic experience, this job is a doddle.
