Hi
We run a call centre and have some ISDN circuits for our main lines. Over the last 6 months, the ISDN lines randomly come up unavailable when people call in. One call in will say unavailable and the next will be ok and then they go off again, we do not seem to see a pattern but it always comes right when we downpower the ISDN unit. Chorus have replaced the unit but the problem still persists. Any idea on what this is? We have had the same looking ISDN boxes on the wall for the last 8 years, is there something new and better we should have?