We have Trunk group setup to forward to an extension. Every month for the last 3 months it stops working. I call our vendor the swear it isn't them but after i make the call it eventually starts working. They say the problem is our phone syste.

I read somewhere a way to dial the number directly from a station phone to test the number leaving our system.

Right now the number just rings, i want to test if i dial the number from our system if it works.

Does anyone know what this method is?