I have just configured PRI for a client but he complains that calls drop intermitently 30% of the time. One time he had to unplug the E1 cable and plug back to the router to reset the trunk.Do you think it could be a problem from the providers, although they claim everything is ok at their end or is there a parameter on the router that could be responsible something like that?

Can someone please help with a suggestion? Cos my client has refused to sign me off.